Title:	Testing for Shiny Applications
Version:	0.4.1
Description:	Automated unit testing of Shiny applications through a headless 'Chromium' browser.
License:	MIT + file LICENSE
Encoding:	UTF-8
Language:	en-US
RoxygenNote:	7.3.2
URL:	https://rstudio.github.io/shinytest2/, https://github.com/rstudio/shinytest2
BugReports:	https://github.com/rstudio/shinytest2/issues
VignetteBuilder:	knitr
Depends:	testthat (≥ 3.1.2)
Imports:	R6 (≥ 2.4.0), callr, checkmate (≥ 2.0.0), chromote (≥ 0.5.0), cli, fs, globals (≥ 0.14.0), httr, jsonlite, pingr, rlang (≥ 1.0.0), rmarkdown, shiny, withr, lifecycle
Suggests:	deSolve, diffobj, ggplot2, knitr, plotly, png, rstudioapi, shinyWidgets, shinytest (≥ 1.5.1), shinyvalidate (≥ 0.1.2), showimage, usethis, vdiffr (≥ 1.0.0), spelling
Config/Needs/check:	rstudio/shiny, bslib
Config/Needs/website:	pkgdown, tidyverse/tidytemplate
Config/testthat/edition:	3
Collate:	'R6-helper.R' 'app-driver-chromote.R' 'app-driver-dir.R' 'app-driver-expect-download.R' 'app-driver-expect-js.R' 'app-driver-expect-screenshot.R' 'app-driver-expect-unique-names.R' 'app-driver-expect-values.R' 'app-driver-get-log.R' 'app-driver-initialize.R' 'app-driver-log-message.R' 'app-driver-message.R' 'app-driver-node.R' 'app-driver-set-inputs.R' 'app-driver-start.R' 'app-driver-stop.R' 'app-driver-timeout.R' 'app-driver-upload-file.R' 'app-driver-variant.R' 'app-driver-wait.R' 'app-driver-window.R' 'app-driver.R' 'chromote-methods.R' 'compare-screenshot-threshold.R' 'cpp11.R' 'expect-snapshot.R' 'expr-recurse.R' 'httr.R' 'migrate.R' 'missing-value.R' 'utils.R' 'platform.R' 'record-test-unique-name.R' 'record-test.R' 'rstudio.R' 'save-app.R' 'shiny-browser.R' 'shinytest2-logs.R' 'shinytest2-package.R' 'test-app.R' 'use.R'
LinkingTo:	cpp11
NeedsCompilation:	yes
Packaged:	2025-04-11 21:20:56 UTC; barret
Author:	Barret Schloerke [cre, aut], Posit Software, PBC [cph, fnd], Winston Chang [ctb] (Original author to rstudio/shinytest), Gábor Csárdi [ctb] (Original author to rstudio/shinytest), Hadley Wickham [ctb] (Original author to rstudio/shinytest), Mango Solutions [cph, ccp] (Original author to rstudio/shinytest)
Maintainer:	Barret Schloerke <barret@posit.co>
Repository:	CRAN
Date/Publication:	2025-04-11 22:20:02 UTC

Drive a Shiny application

Description

This class starts a Shiny app in a new R session, along with chromote's headless browser that can be used to simulate user actions. This provides a full simulation of a Shiny app so that you can test user interactions with a live app.

Methods described below are ordered by perceived popularity. Expect methods are grouped next to their corresponding get methods.

Vignettes

Please see Testing in depth for more details about the different expectation methods.

Please see Robust testing for more details about the cost / benefits for each expectation method.

Test mode

To have your AppDriver retrieve values from your Shiny app, be sure to set shiny::runApp(test.mode = TRUE) when running your Shiny app.

If you are deploying your Shiny app where you do not have control over the call to shiny::runApp(), you can set options(shiny.testmode = TRUE) in a .Rprofile file within your Shiny app directory.

Start-up failure

If the app throws an error during initialization, the AppDriver will be stored in rlang::last_error()$app. This allows for the "failure to initialize" to be signaled while also allowing for the app to be retrieved after any initialization error has been thrown.

Exporting reactive values

Reactive values from within your Shiny application can be exported using the method: shiny::exportTestValues(). This underutilized method exposes internal values of your app without needing to create a corresponding input value or output value.

For example:

library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Pythagorean theorem"),
    numericInput("A", "A", 3),
    numericInput("B", "B", 4),
    verbatimTextOutput("C"),
  ),
  function(input, output) {
    a_squared <- reactive({ req(input$A); input$A * input$A })
    b_squared <- reactive({ req(input$B); input$B * input$B })
    c_squared <- reactive({ a_squared() + b_squared() })
    c_value <- reactive({ sqrt(c_squared()) })
    output$C <- renderText({ c_value() })

    exportTestValues(
      a_squared = { a_squared() },
      b_squared = { b_squared() },
      c_squared = { c_squared() }
    )
  }
)

app <- AppDriver$new(shiny_app)

init_vals <- app$get_values()
str(init_vals)
#> List of 3
#> $ input :List of 2
#> ..$ A: int 3
#> ..$ B: int 4
#> $ output:List of 1
#> ..$ C: chr "5"
#> $ export:List of 3
#> ..$ a_squared: int 9
#> ..$ b_squared: int 16
#> ..$ c_squared: int 25

These exported test values are only exposed when shiny::runApp(test.mode = TRUE) is set. shinytest2 sets this variable when running Shiny based app or document.

testthat wrappers

The two main expectation methods: ⁠$expect_values()⁠ and ⁠$expect_screenshot()⁠ eventually wrap testthat::expect_snapshot_file().

Their underlying logic is similar to:

skip_on_cran() # AppDriver

## Expect values
tmpfile <- tempfile(fileext = ".json")
jsonlite::write_json(app$get_values(), tmpfile)
expect_snapshot_file(
  tmpfile,
  variant = app$get_variant(),
  compare = testthat::compare_file_text
)


## Expect screenshot
tmpfile <- tempfile(fileext = ".png")
app$get_screenshot(tmpfile)
expect_snapshot_file(
  tmpfile,
  variant = app$get_variant(),
  compare = testthat::compare_file_binary
)

To update the snapshot values, you will need to run a variation of testthat::snapshot_review().

Methods

Public methods

• AppDriver$new()

• AppDriver$view()

• AppDriver$click()

• AppDriver$set_inputs()

• AppDriver$upload_file()

• AppDriver$expect_values()

• AppDriver$get_value()

• AppDriver$get_values()

• AppDriver$expect_download()

• AppDriver$get_download()

• AppDriver$expect_text()

• AppDriver$get_text()

• AppDriver$expect_html()

• AppDriver$get_html()

• AppDriver$expect_js()

• AppDriver$get_js()

• AppDriver$run_js()

• AppDriver$expect_screenshot()

• AppDriver$get_screenshot()

• AppDriver$wait_for_idle()

• AppDriver$wait_for_value()

• AppDriver$wait_for_js()

• AppDriver$expect_unique_names()

• AppDriver$get_dir()

• AppDriver$get_url()

• AppDriver$get_window_size()

• AppDriver$set_window_size()

• AppDriver$get_chromote_session()

• AppDriver$get_variant()

• AppDriver$get_logs()

• AppDriver$log_message()

• AppDriver$stop()

Method new()

Initialize an AppDriver object

Usage

AppDriver$new(
  app_dir = testthat::test_path("../../"),
  ...,
  name = NULL,
  variant = missing_arg(),
  seed = NULL,
  load_timeout = missing_arg(),
  timeout = missing_arg(),
  wait = TRUE,
  screenshot_args = missing_arg(),
  expect_values_screenshot_args = TRUE,
  check_names = TRUE,
  view = missing_arg(),
  height = NULL,
  width = NULL,
  clean_logs = TRUE,
  shiny_args = list(),
  render_args = NULL,
  options = list()
)

Arguments

Returns

An object with class AppDriver and the many methods described in this documentation.

Examples

\dontrun{
# Create an AppDriver from the Shiny app in the current directory
app <- AppDriver()

# Create an AppDriver object from a different Shiny app directory
example_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver(example_app)

# Expect consistent inital values
app$expect_values()
}

Method view()

View the Shiny application

Calls ⁠$view()⁠ on the chromote::ChromoteSession object to view your Shiny application in a Chrome browser.

This method is very helpful for debugging while writing your tests.

Usage

AppDriver$view()

Examples

\dontrun{
# Open app in Chrome
app$view()
}

Method click()

Click an element

Find a Shiny input/output value or DOM CSS selector and click it using the DOM method TAG.click().

This method can be used to click input buttons and other elements that need to simulate a click action.

Usage

AppDriver$click(
  input = missing_arg(),
  output = missing_arg(),
  selector = missing_arg(),
  ...
)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

tmpfile <- write.csv(cars, "cars.csv")
app$upload_file(file1 = tmpfile)
cat(app$get_text("#view"))
app$set_inputs(dataset = "cars", obs = 6)
app$click("update")
cat(app$get_text("#view"))
}

Method set_inputs()

Set input values

Set Shiny inputs by sending the value to the Chrome browser and programmatically updating the values. Given wait_ = TRUE, the method will not return until an output value has been updated.

Usage

AppDriver$set_inputs(
  ...,
  wait_ = TRUE,
  timeout_ = missing_arg(),
  allow_no_input_binding_ = FALSE,
  priority_ = c("input", "event")
)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

cat(app$get_text("#view"))
app$set_inputs(dataset = "cars", obs = 6)
app$click("update")
cat(app$get_text("#view"))
}

Method upload_file()

Upload a file

Uploads a file to the specified file input.

Usage

AppDriver$upload_file(..., wait_ = TRUE, timeout_ = missing_arg())

Arguments

Examples

\dontrun{
app_path <- system.file("examples/09_upload", package = "shiny")
app <- AppDriver$new(app_path)

# Save example file
tmpfile <- tempfile(fileext = ".csv")
write.csv(cars, tmpfile, row.names = FALSE)

# Upload file to input named: file1
app$upload_file(file1 = tmpfile)
}

Method expect_values()

Expect input, output, and export values

A JSON snapshot is saved of given the results from the underlying call to ⁠$get_values()⁠.

Note, values that contain environments or other values that will have trouble serializing may not work well. Instead, these objects should be manually inspected and have their components tested individually.

Please see Robust testing for more details.

Usage

AppDriver$expect_values(
  ...,
  input = missing_arg(),
  output = missing_arg(),
  export = missing_arg(),
  screenshot_args = missing_arg(),
  name = NULL,
  transform = NULL,
  cran = deprecated()
)

Arguments

Returns

The result of the snapshot expectation

Examples

\dontrun{
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Pythagorean theorem"),
    numericInput("A", "A", 3),
    numericInput("B", "B", 4),
    verbatimTextOutput("C"),
  ),
  function(input, output) {
    a_squared <- reactive({ req(input$A); input$A * input$A })
    b_squared <- reactive({ req(input$B); input$B * input$B })
    c_squared <- reactive({ a_squared() + b_squared() })
    c_value <- reactive({ sqrt(c_squared()) })
    output$C <- renderText({ c_value() })

    exportTestValues(
      a_squared = { a_squared() },
      b_squared = { b_squared() },
      c_squared = { c_squared() }
    )
  }
)

app <- AppDriver$new(shiny_app)

# Snapshot all known values
app$expect_values()

# Snapshot only `export` values
app$expect_values(export = TRUE)

# Snapshot values `"A"` from `input` and `"C"` from `output`
app$expect_values(input = "A", output = "C")
}

Method get_value()

Get a single input, output, or export value

This is a helper function around ⁠$get_values()⁠ to retrieve a single input, output, or export value. Only a single input, output, or export value can be used.

Note, values that contain environments or other values that will have trouble serializing to RDS may not work well.

Usage

AppDriver$get_value(
  ...,
  input = missing_arg(),
  output = missing_arg(),
  export = missing_arg(),
  hash_images = FALSE
)

Arguments

Returns

The requested input, output, or export value.

Examples

\dontrun{
app_path <- system.file("examples/04_mpg", package = "shiny")
app <- AppDriver$new(app_path)

# Retrieve a single value
app$get_value(output = "caption")
#> [1] "mpg ~ cyl"
# Equivalent code using `$get_values()`
app$get_values(output = "caption")$output$caption
#> [1] "mpg ~ cyl"
}

Method get_values()

Get input, output, and export values

Retrieves a list of all known input, output, or export values. This method is a core method when inspecting your Shiny app.

Note, values that contain environments or other values that will have trouble serializing may not work well.

Usage

AppDriver$get_values(
  ...,
  input = missing_arg(),
  output = missing_arg(),
  export = missing_arg(),
  hash_images = FALSE
)

Arguments

Returns

A named list of all inputs, outputs, and export values.

Examples

\dontrun{
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Pythagorean theorem"),
    numericInput("A", "A", 3),
    numericInput("B", "B", 4),
    verbatimTextOutput("C"),
  ),
  function(input, output) {
    a_squared <- reactive({ req(input$A); input$A * input$A })
    b_squared <- reactive({ req(input$B); input$B * input$B })
    c_squared <- reactive({ a_squared() + b_squared() })
    c_value <- reactive({ sqrt(c_squared()) })
    output$C <- renderText({ c_value() })

    exportTestValues(
      a_squared = { a_squared() },
      b_squared = { b_squared() },
      c_squared = { c_squared() }
    )
  }
)

app <- AppDriver$new(shiny_app)

# Show all known values
str(app$get_values())
#> List of 3
#> $ input :List of 2
#> ..$ A: int 3
#> ..$ B: int 4
#> $ output:List of 1
#> ..$ C: chr "5"
#> $ export:List of 3
#> ..$ a_squared: int 9
#> ..$ b_squared: int 16
#> ..$ c_squared: int 25

# Get only `export` values
str(app$get_values(export = TRUE))
#> List of 1
#> $ export:List of 3
#> ..$ a_squared: int 9
#> ..$ b_squared: int 16
#> ..$ c_squared: int 25

# Get values `"A"` from `input` and `"C"` from `output`
str(app$get_values(input = "A", output = "C"))
#> List of 2
#> $ input :List of 1
#> ..$ A: int 3
#> $ output:List of 1
#> ..$ C: chr "5"
}

Method expect_download()

Expect a downloadable file

Given a shiny::downloadButton()/shiny::downloadLink() output ID, the corresponding file will be downloaded and saved as a snapshot file.

Usage

AppDriver$expect_download(
  output,
  ...,
  compare = NULL,
  name = NULL,
  transform = NULL,
  cran = deprecated()
)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/10_download", package = "shiny")
app <- AppDriver$new(app_path)

# Save snapshot of rock.csv as 001.download
# Save snapshot value of `rock.csv` to capture default file name
app$expect_download("downloadData", compare = testthat::compare_file_text)
}

Method get_download()

Get downloadable file

Given a shiny::downloadButton()/shiny::downloadLink() output ID, the corresponding file will be downloaded and saved as a file.

Usage

AppDriver$get_download(output, filename = NULL)

Arguments

Returns

⁠$get_download()⁠ will return the final save location of the file. This location can change depending on the value of filename and response headers.

Location logic:

• If filename is not NULL, filename will be returned.

• If a content-disposition filename is provided, then a temp file containing this filename will be returned.

• Otherwise, a temp file ending in .download will be returned.

Examples

\dontrun{
app_path <- system.file("examples/10_download", package = "shiny")
app <- AppDriver$new(app_path)

# Get rock.csv as a tempfile
app$get_download("downloadData")
#> [1] "/TEMP/PATH/rock.csv"

# Get rock.csv as a "./myfile.csv"
app$get_download("downloadData", filename = "./myfile.csv")
#> [1] "./myfile.csv"
}

Method expect_text()

Expect snapshot of UI text

⁠$expect_text()⁠ will extract the text value of all matching elements via TAG.textContent and store them in a snapshot file. This method is more robust to internal package change as only the text values will be maintained. Note, this method will not retrieve any ⁠<input />⁠ value's text content, e.g. text inputs or text areas, as the input values are not stored in the live HTML.

When possible, use ⁠$expect_text()⁠ over ⁠$expect_html()⁠ to allow package authors room to alter their HTML structures. The resulting array of TAG.textContent values found will be stored in a snapshot file.

Please see Robust testing for more details.

Usage

AppDriver$expect_text(selector, ..., cran = deprecated())

Arguments

Examples

\dontrun{
hello_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(hello_app)

# Make a snapshot of `"Hello Shiny!"`
app$expect_text("h2")
}

Method get_text()

Get UI text

⁠$get_text()⁠ will extract the text value of all matching elements via TAG.textContent. Note, this method will not retrieve any ⁠<input />⁠ value's text content, e.g. text inputs or text areas, as the input values are not stored in the live HTML.

Usage

AppDriver$get_text(selector)

Arguments

Returns

A vector of character values

Examples

\dontrun{
hello_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(hello_app)

app$get_text("h2")
#> [1] "Hello Shiny!"
}

Method expect_html()

Expect snapshot of UI HTML

⁠$expect_html()⁠ will extract the full DOM structures of each matching element and store them in a snapshot file. This method captures internal DOM structure which may be brittle to changes by external authors or dependencies.

Note, this method will not retrieve any ⁠<input />⁠ value's text content, e.g. text inputs or text areas, as the input values are not stored in the live HTML.

When possible, use ⁠$expect_text()⁠ over ⁠$expect_html()⁠ to allow package authors room to alter their HTML structures. The resulting array of TAG.textContent values found will be stored in a snapshot file.

Please see Robust testing for more details.

Usage

AppDriver$expect_html(selector, ..., outer_html = TRUE, cran = deprecated())

Arguments

Examples

\dontrun{
app_path <- system.file("examples/04_mpg", package = "shiny")
app <- AppDriver$new(app_path)

# Save a snapshot of the `caption` output
app$expect_html("#caption")
}

Method get_html()

Get UI HTML

⁠$get()⁠ will extract the full DOM structures of each matching element. This method captures internal DOM structure which may be brittle to changes by external authors or dependencies.

Note, this method will not retrieve any ⁠<input />⁠ value's text content, e.g. text inputs or text areas, as the input values are not stored in the live HTML.

Please see Robust testing for more details.

Usage

AppDriver$get_html(selector, ..., outer_html = TRUE)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/03_reactivity", package = "shiny")
app <- AppDriver$new(app_path, check_names = FALSE)

app$set_inputs(caption = "Custom value!")
cat(app$get_html(".shiny-input-container")[1])
#> <div class="form-group shiny-input-container">
#>   <label class="control-label" id="caption-label" for="caption">Caption:</label>
#>   <input id="caption" type="text" class="form-control shiny-bound-input" value="Data Summary">
#> </div>
## ^^ No update to the DOM of `caption`
}

Method expect_js()

Expect snapshot of JavaScript script output

This is a building block function that may be called by other functions. For example, ⁠$expect_text()⁠ and ⁠$expect_html()⁠ are thin wrappers around this function.

Once the script has executed, the JSON result will be saved to a snapshot file.

Usage

AppDriver$expect_js(
  script = missing_arg(),
  ...,
  file = missing_arg(),
  timeout = missing_arg(),
  pre_snapshot = NULL,
  cran = deprecated()
)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

# Track how many clicks are given to `#update` button
app$run_js("
  window.test_counter = 0;
  $('#update').click(() => window.test_counter++);
")
app$set_inputs(obs = 20)
# Click the update button, incrementing the counter
app$click("update")
# Save a snapshot of number of clicks (1)
app$expect_js("window.test_counter;")
}

Method get_js()

Execute JavaScript code in the browser and return the result

This function will block the local R session until the code has finished executing its tick in the browser. If a Promise is returned from the script, ⁠$get_js()⁠ will wait for the promise to resolve. To have JavaScript code execute asynchronously, wrap the code in a Promise object and have the script return an atomic value.

Arguments will have to be inserted into the script as there is not access to arguments. This can be done with commands like paste(). If using glue::glue(), be sure to use uncommon .open and .close values to avoid having to double all ⁠{⁠ and ⁠}⁠.

Usage

AppDriver$get_js(
  script = missing_arg(),
  ...,
  file = missing_arg(),
  timeout = missing_arg()
)

Arguments

Returns

Result of the script (or file contents)

Examples

\dontrun{
library(shiny)
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Execute JavaScript code in the app's browser
app$get_js("1 + 1;")
#> [1] 2

# Execute a JavaScript Promise. Return the resolved value.
app$get_js("
  new Promise((resolve) => {
    setTimeout(() => resolve(1 + 1), 1000)
  }).
  then((value) => value + 1);
")
#> [1] 3

# With escaped arguments
loc_field <- "hostname"
js_txt <- paste0("window.location[", jsonlite::toJSON(loc_field, auto_unbox = TRUE), "]")
app$get_js(js_txt)
#> [1] "127.0.0.1"

# With `glue::glue()`
js_txt <- glue::glue_data(
  lapply(
    list(x = 40, y = 2),
    jsonlite::toJSON,
    auto_unbox = TRUE
  ),
  .open = "<", .close = ">",
  "let answer = function(a, b) {\n",
  "  return a + b;\n",
  "};\n",
  "answer(<x>, <y>);\n"
)
app$get_js(js_txt)
#> [1] 42
}

Method run_js()

Execute JavaScript code in the browser

This function will block the local R session until the code has finished executing its tick in the browser.

The final result of the code will be ignored and not returned to the R session.

Usage

AppDriver$run_js(
  script = missing_arg(),
  ...,
  file = missing_arg(),
  timeout = missing_arg()
)

Arguments

Examples

\dontrun{
library(shiny)
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Get JavaScript answer from the app's browser
app$get_js("1 + 1")
#> [1] 2
# Execute JavaScript code in the app's browser
app$run_js("1 + 1")
# (Returns `app` invisibly)

# With escaped arguments
loc_field <- "hostname"
js_txt <- paste0("window.location[", jsonlite::toJSON(loc_field, auto_unbox = TRUE), "]")
app$run_js(js_txt)
app$get_js(js_txt)
#> [1] "127.0.0.1"
}

Method expect_screenshot()

Expect a screenshot of the Shiny application

This method takes a screenshot of the application (of only the selector area) and compares the image to the expected image.

Please be aware that this method is very brittle to changes outside of your Shiny application. These changes can include:

• running on a different R version

• running on a different in operating system

• using a different default system font

• using different package versions These differences are explicitly clear when working with plots.

Unless absolutely necessary for application consistency, it is strongly recommended to use other expectation methods.

Usage

AppDriver$expect_screenshot(
  ...,
  threshold = getOption("shinytest2.compare_screenshot.threshold", NULL),
  kernel_size = getOption("shinytest2.compare_screenshot.kernel_size", 5),
  screenshot_args = missing_arg(),
  delay = missing_arg(),
  selector = missing_arg(),
  compare = missing_arg(),
  quiet = FALSE,
  name = NULL,
  cran = deprecated()
)

Arguments

Examples

\dontrun{
# These example lines should be performed in a `./tests/testthat`
# test file so that snapshot files can be properly saved

app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path, variant = platform_variant())

# Expect a full size screenshot to be pixel perfect
app$expect_screenshot()

# Images are brittle when containing plots
app$expect_screenshot(selector = "#distPlot")

# Test with more threshold in pixel value differences
# Helps with rounded corners
app$expect_screenshot(threshold = 10)

# Equivalent expectations
app$expect_screenshot() # default
app$expect_screenshot(threshold = NULL)
app$expect_screenshot(compare = testthat::compare_file_binary)
expect_snapshot_file(
  app$get_screenshot(),
  variant = app$get_variant(),
  compare = testthat::compare_file_binary
)

# Equivalent expectations
app$expect_screenshot(threshold = 3, kernel_size = 5)
app$expect_screenshot(compare = function(old, new) {
  compare_screenshot_threshold(
    old, new,
    threshold = 3,
    kernel_size = 5
  )
})
expect_screenshot_file(
  app$get_screenshot(),
  variant = app$get_variant(),
  compare = function(old, new) {
    compare_screenshot_threshold(
      old, new,
      threshold = 3,
      kernel_size = 5
    )
  }
)

# Take a screenshot of the entire scrollable area
app$expect_screenshot()
app$expect_screenshot(selector = "scrollable_area")

## Take a screenshot of the current viewport
# Shrink the window to be smaller than the app
app$set_window_size(400, 500)
# Scroll the viewport just a bit
app$run_js("window.scroll(30, 70)")
# Take screenshot of browser viewport
app$expect_screenshot(selector = "viewport")
}

Method get_screenshot()

Take a screenshot

Take a screenshot of the Shiny application.

Usage

AppDriver$get_screenshot(
  file = NULL,
  ...,
  screenshot_args = missing_arg(),
  delay = missing_arg(),
  selector = missing_arg()
)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

# Display in graphics device
app$get_screenshot()

# Update bins then display `"disPlot"` in graphics device
app$set_inputs(bins = 10)
app$get_screenshot(selector = "#distPlot")

# Save screenshot to file and view it
tmpfile <- tempfile(fileext = ".png")
app$get_screenshot(tmpfile)
showimage::show_image(tmpfile)
}

Method wait_for_idle()

Wait for Shiny to not be busy (idle) for a set amount of time

Waits until Shiny has not been busy for a set duration of time, e.g. no reactivity is updating or has occurred.

This is useful, for example, when waiting for your application to initialize or if you've resized the window with ⁠$set_window_size()⁠ and want to make sure all plot redrawing is complete before take a screenshot.

By default,

• ⁠$new(wait = TRUE)⁠ waits for Shiny to not be busy after initializing the application

• ⁠$set_window_size(wait = TRUE)⁠ waits for Shiny to not be busy after resizing the window.)

Usage

AppDriver$wait_for_idle(duration = 500, timeout = missing_arg())

Arguments

Returns

invisible(self) if Shiny stabilizes within the timeout. Otherwise an error will be thrown

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

pre_value <- app$get_value(output = "distPlot")
# Update bins value
app$set_inputs(bins = 10, wait_ = FALSE)
middle_value <- app$get_value(output = "distPlot")
app$wait_for_idle()
post_value <- app$get_value(output = "distPlot")

# No guarantee that these values are different
identical(pre_value, middle_value)
# Will not be equal
identical(pre_value, post_value)

# ---------------------
## Change the screen size to trigger a plot update
pre_value <- app$get_value(output = "distPlot")
app$set_window_size(height = 1080, width = 1920, wait = FALSE)
middle_value <- app$get_value(output = "distPlot")
app$wait_for_idle()
post_value <- app$get_value(output = "distPlot")

# No guarantee that these values are different
identical(pre_value, middle_value)
# Will not be equal
identical(pre_value, post_value)
}

Method wait_for_value()

Wait for a new Shiny value

Waits until an input, output, or export Shiny value is not one of ignored values, or the timeout is reached.

Only a single input, output, or export value may be used.

This function can be useful in helping determine if an application has finished processing a complex reactive situation.

Usage

AppDriver$wait_for_value(
  ...,
  input = missing_arg(),
  output = missing_arg(),
  export = missing_arg(),
  ignore = list(NULL, ""),
  timeout = missing_arg(),
  interval = 400
)

Arguments

Returns

Newly found value

Examples

\dontrun{
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Dynamic output"),
    actionButton("display", "Display UI"),
    uiOutput("dym1"),
  ),
  function(input, output) {
    output$dym1 <- renderUI({
      req(input$display)
      Sys.sleep(runif(1, max = 2)) # Artificial calculations
      tagList(
        sliderInput("slider1", "Slider #1", 0, 100, 25),
        uiOutput("dym2")
      )
    })
    output$dym2 <- renderUI({
      Sys.sleep(runif(1, max = 2)) # Artificial calculations
      tagList(
        sliderInput("slider2", "Slider #2", 0, 100, 50),
        "Total:", verbatimTextOutput("total")
      )
    })
    output$total <- renderText({
      req(input$slider1, input$slider2)
      input$slider1 + input$slider2
    })
  }
)

app <- AppDriver$new(shiny_app)

# Create UI / output values
app$click("display")
# Wait for total to be calculated (or have a non-NULL value)
new_total_value <- app$wait_for_value(output = "total")
#> [1] "75"
app$get_value(output = "total")
#> [1] "75"
}

Method wait_for_js()

Wait for a JavaScript expression to be true

Waits until a JavaScript expression evaluates to true or the timeout is exceeded.

Usage

AppDriver$wait_for_js(script, timeout = missing_arg(), interval = 100)

Arguments

Returns

invisible(self) if expression evaluates to true without error within the timeout. Otherwise an error will be thrown

Examples

\dontrun{
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Contrived example:
# Wait until `Date.now()` returns a number that ends in a 5. (0 - 10 seconds)
system.time(
  app$wait_for_js("Math.floor((Date.now() / 1000) % 10) == 5;")
)

## A second example where we run the contents of a JavaScript file
## and use the result to wait for a condition
app$run_js(file = "complicated_file.js")
app$wait_for_js("complicated_condition();")
}

Method expect_unique_names()

Expect unique input and output names.

If the HTML has duplicate input or output elements with matching id values, this function will throw an error. It is similar to AppDriver$new(check_names = TRUE), but asserts that no warnings are displayed.

This method will not throw if a single input and a single output have the same name.

Usage

AppDriver$expect_unique_names()

Examples

\dontrun{
shiny_app <- shinyApp(
  ui = fluidPage(
    # Duplicate input IDs: `"text"`
    textInput("text", "Text 1"),
    textInput("text", "Text 2")
  ),
  server = function(input, output) {
    # empty
  }
)
# Initial checking for unique names (default behavior)
app <- AppDriver$new(shiny_app, check_names = TRUE)
#> Warning:
#> ! Shiny inputs should have unique HTML id values.
#> i The following HTML id values are not unique:
#> • text
app$stop()

# Manually assert that all names are unique
app <- AppDriver$new(shiny_app, check_names = FALSE)
app$expect_unique_names()
#> Error: `app_check_unique_names(self, private)` threw an unexpected warning.
#> Message: ! Shiny inputs should have unique HTML id values.
#> i The following HTML id values are not unique:
#>   • text
#> Class:   rlang_warning/warning/condition
app$stop()
}

Method get_dir()

Retrieve the Shiny app path

Usage

AppDriver$get_dir()

Returns

The directory containing the Shiny application or Shiny runtime document. If a URL was provided to app_dir during initialization, the current directory will be returned.

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

identical(app$get_dir(), app_path)
#> [1] TRUE
}

Method get_url()

Retrieve the Shiny app URL

Usage

AppDriver$get_url()

Returns

URL where the Shiny app is being hosted

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

browseURL(app$get_url())
}

Method get_window_size()

Get window size

Get current size of the browser window, as list of numeric scalars named width and height.

Usage

AppDriver$get_window_size()

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

app$get_window_size()
#> $width
#> [1] 992
#>
#> $height
#> [1] 1323
}

Method set_window_size()

Sets size of the browser window.

Usage

AppDriver$set_window_size(width, height, wait = TRUE)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
# Set init window size
app <- AppDriver$new(app_path, height = 1400, width = 1000)

app$get_window_size()
#> $width
#> [1] 1000
#>
#> $height
#> [1] 1400

# Manually set the window size
app$set_window_size(height = 1080, width = 1920)
app$get_window_size()
#> $width
#> [1] 1920
#>
#> $height
#> [1] 1080
}

Method get_chromote_session()

Get Chromote Session

Get the chromote::ChromoteSession object from the chromote package.

Usage

AppDriver$get_chromote_session()

Returns

chromote::ChromoteSession R6 object

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

b <- app$get_chromote_session()
b$Runtime$evaluate("1 + 1")
#> $result
#> $result$type
#> [1] "number"
#>
#> $result$value
#> [1] 2
#>
#> $result$description
#> [1] "2"
}

Method get_variant()

Get the variant

Get the variant supplied during initialization

Usage

AppDriver$get_variant()

Returns

The variant value supplied during initialization or NULL if no value was supplied.

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")

app <- AppDriver$new(app_path)

app$get_variant()
#> NULL

app <- AppDriver$new(app_path, variant = platform_variant())
app$get_variant()
#> [1] "mac-4.1"
}

Method get_logs()

Get all logs

Retrieve all of the debug logs that have been recorded.

Usage

AppDriver$get_logs()

Returns

A data.frame with the following columns:

• workerid: The shiny worker ID found within the browser

• timestamp: POSIXct timestamp of the message

• location: The location of the message was found. One of three values:

  • "shinytest2": Occurs when ⁠$log_message()⁠ is called

  • "shiny": stdin and stdout messages from the Shiny server. Note message() output is sent to stdout.

  • "chromote": Captured by the chromote event handlers. See console API, exception thrown, websocket sent, and websocket received for more details

• level: For a given location, there are different types of log levels.

  • "shinytest2": "log"; Only log messages are captured.

  • "shiny": "stdout" or "stderr"; Note, message() output is sent to stderr.

  • "chromote": Correspond to any level of a JavaScript console.LEVEL() function call. Typically, these are "log"and"error"⁠but can include⁠"info"⁠, ⁠"debug"⁠, and ⁠"warn"⁠. If ⁠options(shiny.trace = TRUE)⁠, then the level will recorded as ⁠"websocket"'.

Examples

\dontrun{
app1 <- AppDriver$new(system.file("examples/01_hello", package = "shiny"))

app1$get_logs()
#> {shinytest2} R  info   10:00:28.86 Start AppDriver initialization
#> {shinytest2} R  info   10:00:28.86 Starting Shiny app
#> {shinytest2} R  info   10:00:29.76 Creating new ChromoteSession
#> {shinytest2} R  info   10:00:30.56 Navigating to Shiny app
#> {shinytest2} R  info   10:00:30.70 Injecting shiny-tracer.js
#> {chromote}   JS info   10:00:30.75 shinytest2; jQuery found
#> {chromote}   JS info   10:00:30.77 shinytest2; Waiting for shiny session to connect
#> {chromote}   JS info   10:00:30.77 shinytest2; Loaded
#> {shinytest2} R  info   10:00:30.77 Waiting for Shiny to become ready
#> {chromote}   JS info   10:00:30.90 shinytest2; Connected
#> {chromote}   JS info   10:00:30.95 shinytest2; shiny:busy
#> {shinytest2} R  info   10:00:30.98 Waiting for Shiny to become idle for 200ms within 15000ms
#> {chromote}   JS info   10:00:30.98 shinytest2; Waiting for Shiny to be stable
#> {chromote}   JS info   10:00:31.37 shinytest2; shiny:idle
#> {chromote}   JS info   10:00:31.38 shinytest2; shiny:value distPlot
#> {chromote}   JS info   10:00:31.57 shinytest2; Shiny has been idle for 200ms
#> {shinytest2} R  info   10:00:31.57 Shiny app started
#> {shiny}      R  stderr ----------- Loading required package: shiny
#> {shiny}      R  stderr ----------- Running application in test mode.
#> {shiny}      R  stderr -----------
#> {shiny}      R  stderr ----------- Listening on http://127.0.0.1:4679


# To capture all websocket traffic, set `options = list(shiny.trace = TRUE)`
app2 <- AppDriver$new(
  system.file("examples/01_hello", package = "shiny"),
  options = list(shiny.trace = TRUE)
)

app2$get_logs()
## (All WebSocket messages have been replaced with `WEBSOCKET_MSG` in example below)
#> {shinytest2} R  info      10:01:57.49 Start AppDriver initialization
#> {shinytest2} R  info      10:01:57.50 Starting Shiny app
#> {shinytest2} R  info      10:01:58.20 Creating new ChromoteSession
#> {shinytest2} R  info      10:01:58.35 Navigating to Shiny app
#> {shinytest2} R  info      10:01:58.47 Injecting shiny-tracer.js
#> {chromote}   JS info      10:01:58.49 shinytest2; jQuery not found
#> {chromote}   JS info      10:01:58.49 shinytest2; Loaded
#> {shinytest2} R  info      10:01:58.50 Waiting for Shiny to become ready
#> {chromote}   JS info      10:01:58.55 shinytest2; jQuery found
#> {chromote}   JS info      10:01:58.55 shinytest2; Waiting for shiny session to connect
#> {chromote}   JS websocket 10:01:58.64 send WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.67 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.67 shinytest2; Connected
#> {chromote}   JS websocket 10:01:58.71 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.72 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.72 shinytest2; shiny:busy
#> {chromote}   JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {shinytest2} R  info      10:01:58.75 Waiting for Shiny to become idle for 200ms within 15000ms
#> {chromote}   JS info      10:01:58.75 shinytest2; Waiting for Shiny to be stable
#> {chromote}   JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.81 shinytest2; shiny:idle
#> {chromote}   JS websocket 10:01:58.82 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.82 shinytest2; shiny:value distPlot
#> {chromote}   JS info      10:01:59.01 shinytest2; Shiny has been idle for 200ms
#> {shinytest2} R  info      10:01:59.01 Shiny app started
#> {shiny}      R  stderr    ----------- Loading required package: shiny
#> {shiny}      R  stderr    ----------- Running application in test mode.
#> {shiny}      R  stderr    -----------
#> {shiny}      R  stderr    ----------- Listening on http://127.0.0.1:4560
#> {shiny}      R  stderr    ----------- SEND {"config":{"workerId":"","sessionId"|truncated
#> {shiny}      R  stderr    ----------- RECV {"method":"init","data":{"bins":30,|truncated
#> {shiny}      R  stderr    ----------- SEND {"custom":{"showcase-src":{"srcref":|truncated
#> {shiny}      R  stderr    ----------- SEND {"busy":"busy"}
#> {shiny}      R  stderr    ----------- SEND {"custom":{"showcase-src":{"srcref":|truncated
#> {shiny}      R  stderr    ----------- SEND {"recalculating":{"name":"distPlot",|truncated
#> {shiny}      R  stderr    ----------- SEND {"recalculating":{"name":"distPlot",|truncated
#> {shiny}      R  stderr    ----------- SEND {"busy":"idle"}
#> {shiny}      R  stderr    ----------- SEND {"errors":{},"values":{"distPlot":|truncated

# The log that is returned is a `data.frame()`.
log <- app2$get_logs()
tibble::glimpse(log)
#> Rows: 43
#> Columns: 5
#> $ workerid  <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, …
#> $ timestamp <dttm> 2022-09-19 10:01:57, 2022-09-19 10:01:57, 2022-09-19 10:01:58, 2022…
#> $ location  <chr> "shinytest2", "shinytest2", "shinytest2", "shinytest2", "shinytest2"…
#> $ level     <chr> "info", "info", "info", "info", "info", "info", "info", "info", "inf…
#> $ message   <chr> "Start AppDriver initialization", "Starting Shiny app", "Creating ne…
#> $ workerid  <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, …
#> $ timestamp <dttm> 2022-03-16 11:09:57, 2022-03-16 11:09:57, 2022-03-16 11:09:…
#> $ location  <chr> "shinytest2", "shinytest2", "shinytest2", "shinytest2", "shi…
#> $ level     <chr> "info", "info", "info", "info", "info", "info", "info", "inf…
#> $ message   <chr> "Start AppDriver initialization", "Starting Shiny app", "Cre…

# It may be filtered to find desired logs
subset(log, level == "websocket")
## (All WebSocket messages have been replaced with `WEBSOCKET_MSG` in example below)
#> {chromote} JS websocket 10:01:58.64 send WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.67 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.71 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.72 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.82 recv WEBSOCKET_MSG
}

Method log_message()

Add a message to the shinytest2 log.

Usage

AppDriver$log_message(message)

Arguments

Examples

\dontrun{
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

app$log_message("Setting bins to smaller value")
app$set_inputs(bins = 10)
app$get_logs()
}

Method stop()

Stop the Shiny application driver

This method stops all known processes:

• The Shiny application in the background R process,

• the background R process hosting the Shiny application, and

• the Chromote Session instance.

To stop your shiny application and return a value from ⁠$stop()⁠, see shiny::stopApp(). This is useful in testing to return context information.

Typically, this can be paired with a button that when clicked will call shiny::stopApp(info) to return info from the test app back to the main R session.

Usage

AppDriver$stop(signal_timeout = missing_arg())

Arguments

Returns

The result of the background process if the Shiny application has already been terminated.

Examples

\dontrun{
rlang::check_installed("reactlog")

library(shiny)
shiny_app <- shinyApp(
  ui = fluidPage(
    actionButton("button", "Stop app and return Reactlog"),
    "Click count:", textOutput("count")
  ),
  server = function(input, output) {
    output$count <- renderText({ input$button })
    observe({
      req(input$button)
      stopApp(shiny::reactlog())
    })
  }
)

app <- AppDriver$new(
  shiny_app,
  # Enable reactlog in background R session
  options = list(shiny.reactlog = TRUE)
)

app$click("button")
rlog <- app$stop()
str(head(rlog, 2))
#> List of 2
#> $ :List of 7
#> ..$ action : chr "define"
#> ..$ reactId: chr "r3"
#> ..$ label  : chr "Theme Counter"
#> ..$ type   : chr "reactiveVal"
#> ..$ value  : chr " num 0"
#> ..$ session: chr "bdc7417f2fc8c84fc05c9518e36fdc44"
#> ..$ time   : num 1.65e+09
#> $ :List of 7
#> ..$ action : chr "define"
#> ..$ reactId: chr "r4"
#> ..$ label  : chr "output$count"
#> .. ..- attr(*, "srcref")= int [1:6] 7 32 7 45 32 45
#> .. ..- attr(*, "srcfile")= chr ""
#> ..$ type   : chr "observer"
#> ..$ value  : chr " NULL"
#> ..$ session: chr "bdc7417f2fc8c84fc05c9518e36fdc44"
#> ..$ time   : num 1.65e+09
}

See Also

platform_variant(), use_shinytest2_test()

Examples

## ------------------------------------------------
## Method `AppDriver$new`
## ------------------------------------------------

## Not run: 
# Create an AppDriver from the Shiny app in the current directory
app <- AppDriver()

# Create an AppDriver object from a different Shiny app directory
example_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver(example_app)

# Expect consistent inital values
app$expect_values()

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$view`
## ------------------------------------------------

## Not run: 
# Open app in Chrome
app$view()

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$click`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

tmpfile <- write.csv(cars, "cars.csv")
app$upload_file(file1 = tmpfile)
cat(app$get_text("#view"))
app$set_inputs(dataset = "cars", obs = 6)
app$click("update")
cat(app$get_text("#view"))

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$set_inputs`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

cat(app$get_text("#view"))
app$set_inputs(dataset = "cars", obs = 6)
app$click("update")
cat(app$get_text("#view"))

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$upload_file`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/09_upload", package = "shiny")
app <- AppDriver$new(app_path)

# Save example file
tmpfile <- tempfile(fileext = ".csv")
write.csv(cars, tmpfile, row.names = FALSE)

# Upload file to input named: file1
app$upload_file(file1 = tmpfile)

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_values`
## ------------------------------------------------

## Not run: 
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Pythagorean theorem"),
    numericInput("A", "A", 3),
    numericInput("B", "B", 4),
    verbatimTextOutput("C"),
  ),
  function(input, output) {
    a_squared <- reactive({ req(input$A); input$A * input$A })
    b_squared <- reactive({ req(input$B); input$B * input$B })
    c_squared <- reactive({ a_squared() + b_squared() })
    c_value <- reactive({ sqrt(c_squared()) })
    output$C <- renderText({ c_value() })

    exportTestValues(
      a_squared = { a_squared() },
      b_squared = { b_squared() },
      c_squared = { c_squared() }
    )
  }
)

app <- AppDriver$new(shiny_app)

# Snapshot all known values
app$expect_values()

# Snapshot only `export` values
app$expect_values(export = TRUE)

# Snapshot values `"A"` from `input` and `"C"` from `output`
app$expect_values(input = "A", output = "C")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_value`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/04_mpg", package = "shiny")
app <- AppDriver$new(app_path)

# Retrieve a single value
app$get_value(output = "caption")
#> [1] "mpg ~ cyl"
# Equivalent code using `$get_values()`
app$get_values(output = "caption")$output$caption
#> [1] "mpg ~ cyl"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_values`
## ------------------------------------------------

## Not run: 
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Pythagorean theorem"),
    numericInput("A", "A", 3),
    numericInput("B", "B", 4),
    verbatimTextOutput("C"),
  ),
  function(input, output) {
    a_squared <- reactive({ req(input$A); input$A * input$A })
    b_squared <- reactive({ req(input$B); input$B * input$B })
    c_squared <- reactive({ a_squared() + b_squared() })
    c_value <- reactive({ sqrt(c_squared()) })
    output$C <- renderText({ c_value() })

    exportTestValues(
      a_squared = { a_squared() },
      b_squared = { b_squared() },
      c_squared = { c_squared() }
    )
  }
)

app <- AppDriver$new(shiny_app)

# Show all known values
str(app$get_values())
#> List of 3
#> $ input :List of 2
#> ..$ A: int 3
#> ..$ B: int 4
#> $ output:List of 1
#> ..$ C: chr "5"
#> $ export:List of 3
#> ..$ a_squared: int 9
#> ..$ b_squared: int 16
#> ..$ c_squared: int 25

# Get only `export` values
str(app$get_values(export = TRUE))
#> List of 1
#> $ export:List of 3
#> ..$ a_squared: int 9
#> ..$ b_squared: int 16
#> ..$ c_squared: int 25

# Get values `"A"` from `input` and `"C"` from `output`
str(app$get_values(input = "A", output = "C"))
#> List of 2
#> $ input :List of 1
#> ..$ A: int 3
#> $ output:List of 1
#> ..$ C: chr "5"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_download`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/10_download", package = "shiny")
app <- AppDriver$new(app_path)

# Save snapshot of rock.csv as 001.download
# Save snapshot value of `rock.csv` to capture default file name
app$expect_download("downloadData", compare = testthat::compare_file_text)

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_download`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/10_download", package = "shiny")
app <- AppDriver$new(app_path)

# Get rock.csv as a tempfile
app$get_download("downloadData")
#> [1] "/TEMP/PATH/rock.csv"

# Get rock.csv as a "./myfile.csv"
app$get_download("downloadData", filename = "./myfile.csv")
#> [1] "./myfile.csv"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_text`
## ------------------------------------------------

## Not run: 
hello_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(hello_app)

# Make a snapshot of `"Hello Shiny!"`
app$expect_text("h2")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_text`
## ------------------------------------------------

## Not run: 
hello_app <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(hello_app)

app$get_text("h2")
#> [1] "Hello Shiny!"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_html`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/04_mpg", package = "shiny")
app <- AppDriver$new(app_path)

# Save a snapshot of the `caption` output
app$expect_html("#caption")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_html`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/03_reactivity", package = "shiny")
app <- AppDriver$new(app_path, check_names = FALSE)

app$set_inputs(caption = "Custom value!")
cat(app$get_html(".shiny-input-container")[1])
#> <div class="form-group shiny-input-container">
#>   <label class="control-label" id="caption-label" for="caption">Caption:</label>
#>   <input id="caption" type="text" class="form-control shiny-bound-input" value="Data Summary">
#> </div>
## ^^ No update to the DOM of `caption`

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_js`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/07_widgets", package = "shiny")
app <- AppDriver$new(app_path)

# Track how many clicks are given to `#update` button
app$run_js("
  window.test_counter = 0;
  $('#update').click(() => window.test_counter++);
")
app$set_inputs(obs = 20)
# Click the update button, incrementing the counter
app$click("update")
# Save a snapshot of number of clicks (1)
app$expect_js("window.test_counter;")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_js`
## ------------------------------------------------

## Not run: 
library(shiny)
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Execute JavaScript code in the app's browser
app$get_js("1 + 1;")
#> [1] 2

# Execute a JavaScript Promise. Return the resolved value.
app$get_js("
  new Promise((resolve) => {
    setTimeout(() => resolve(1 + 1), 1000)
  }).
  then((value) => value + 1);
")
#> [1] 3

# With escaped arguments
loc_field <- "hostname"
js_txt <- paste0("window.location[", jsonlite::toJSON(loc_field, auto_unbox = TRUE), "]")
app$get_js(js_txt)
#> [1] "127.0.0.1"

# With `glue::glue()`
js_txt <- glue::glue_data(
  lapply(
    list(x = 40, y = 2),
    jsonlite::toJSON,
    auto_unbox = TRUE
  ),
  .open = "<", .close = ">",
  "let answer = function(a, b) {\n",
  "  return a + b;\n",
  "};\n",
  "answer(<x>, <y>);\n"
)
app$get_js(js_txt)
#> [1] 42

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$run_js`
## ------------------------------------------------

## Not run: 
library(shiny)
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Get JavaScript answer from the app's browser
app$get_js("1 + 1")
#> [1] 2
# Execute JavaScript code in the app's browser
app$run_js("1 + 1")
# (Returns `app` invisibly)

# With escaped arguments
loc_field <- "hostname"
js_txt <- paste0("window.location[", jsonlite::toJSON(loc_field, auto_unbox = TRUE), "]")
app$run_js(js_txt)
app$get_js(js_txt)
#> [1] "127.0.0.1"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_screenshot`
## ------------------------------------------------

## Not run: 
# These example lines should be performed in a `./tests/testthat`
# test file so that snapshot files can be properly saved

app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path, variant = platform_variant())

# Expect a full size screenshot to be pixel perfect
app$expect_screenshot()

# Images are brittle when containing plots
app$expect_screenshot(selector = "#distPlot")

# Test with more threshold in pixel value differences
# Helps with rounded corners
app$expect_screenshot(threshold = 10)

# Equivalent expectations
app$expect_screenshot() # default
app$expect_screenshot(threshold = NULL)
app$expect_screenshot(compare = testthat::compare_file_binary)
expect_snapshot_file(
  app$get_screenshot(),
  variant = app$get_variant(),
  compare = testthat::compare_file_binary
)

# Equivalent expectations
app$expect_screenshot(threshold = 3, kernel_size = 5)
app$expect_screenshot(compare = function(old, new) {
  compare_screenshot_threshold(
    old, new,
    threshold = 3,
    kernel_size = 5
  )
})
expect_screenshot_file(
  app$get_screenshot(),
  variant = app$get_variant(),
  compare = function(old, new) {
    compare_screenshot_threshold(
      old, new,
      threshold = 3,
      kernel_size = 5
    )
  }
)

# Take a screenshot of the entire scrollable area
app$expect_screenshot()
app$expect_screenshot(selector = "scrollable_area")

## Take a screenshot of the current viewport
# Shrink the window to be smaller than the app
app$set_window_size(400, 500)
# Scroll the viewport just a bit
app$run_js("window.scroll(30, 70)")
# Take screenshot of browser viewport
app$expect_screenshot(selector = "viewport")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_screenshot`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

# Display in graphics device
app$get_screenshot()

# Update bins then display `"disPlot"` in graphics device
app$set_inputs(bins = 10)
app$get_screenshot(selector = "#distPlot")

# Save screenshot to file and view it
tmpfile <- tempfile(fileext = ".png")
app$get_screenshot(tmpfile)
showimage::show_image(tmpfile)

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$wait_for_idle`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

pre_value <- app$get_value(output = "distPlot")
# Update bins value
app$set_inputs(bins = 10, wait_ = FALSE)
middle_value <- app$get_value(output = "distPlot")
app$wait_for_idle()
post_value <- app$get_value(output = "distPlot")

# No guarantee that these values are different
identical(pre_value, middle_value)
# Will not be equal
identical(pre_value, post_value)

# ---------------------
## Change the screen size to trigger a plot update
pre_value <- app$get_value(output = "distPlot")
app$set_window_size(height = 1080, width = 1920, wait = FALSE)
middle_value <- app$get_value(output = "distPlot")
app$wait_for_idle()
post_value <- app$get_value(output = "distPlot")

# No guarantee that these values are different
identical(pre_value, middle_value)
# Will not be equal
identical(pre_value, post_value)

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$wait_for_value`
## ------------------------------------------------

## Not run: 
library(shiny)
shiny_app <- shinyApp(
  fluidPage(
    h1("Dynamic output"),
    actionButton("display", "Display UI"),
    uiOutput("dym1"),
  ),
  function(input, output) {
    output$dym1 <- renderUI({
      req(input$display)
      Sys.sleep(runif(1, max = 2)) # Artificial calculations
      tagList(
        sliderInput("slider1", "Slider #1", 0, 100, 25),
        uiOutput("dym2")
      )
    })
    output$dym2 <- renderUI({
      Sys.sleep(runif(1, max = 2)) # Artificial calculations
      tagList(
        sliderInput("slider2", "Slider #2", 0, 100, 50),
        "Total:", verbatimTextOutput("total")
      )
    })
    output$total <- renderText({
      req(input$slider1, input$slider2)
      input$slider1 + input$slider2
    })
  }
)

app <- AppDriver$new(shiny_app)

# Create UI / output values
app$click("display")
# Wait for total to be calculated (or have a non-NULL value)
new_total_value <- app$wait_for_value(output = "total")
#> [1] "75"
app$get_value(output = "total")
#> [1] "75"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$wait_for_js`
## ------------------------------------------------

## Not run: 
shiny_app <- shinyApp(h1("Empty App"), function(input, output) { })
app <- AppDriver$new(shiny_app)

# Contrived example:
# Wait until `Date.now()` returns a number that ends in a 5. (0 - 10 seconds)
system.time(
  app$wait_for_js("Math.floor((Date.now() / 1000) % 10) == 5;")
)

## A second example where we run the contents of a JavaScript file
## and use the result to wait for a condition
app$run_js(file = "complicated_file.js")
app$wait_for_js("complicated_condition();")

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$expect_unique_names`
## ------------------------------------------------

## Not run: 
shiny_app <- shinyApp(
  ui = fluidPage(
    # Duplicate input IDs: `"text"`
    textInput("text", "Text 1"),
    textInput("text", "Text 2")
  ),
  server = function(input, output) {
    # empty
  }
)
# Initial checking for unique names (default behavior)
app <- AppDriver$new(shiny_app, check_names = TRUE)
#> Warning:
#> ! Shiny inputs should have unique HTML id values.
#> i The following HTML id values are not unique:
#> • text
app$stop()

# Manually assert that all names are unique
app <- AppDriver$new(shiny_app, check_names = FALSE)
app$expect_unique_names()
#> Error: `app_check_unique_names(self, private)` threw an unexpected warning.
#> Message: ! Shiny inputs should have unique HTML id values.
#> i The following HTML id values are not unique:
#>   • text
#> Class:   rlang_warning/warning/condition
app$stop()

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_dir`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

identical(app$get_dir(), app_path)
#> [1] TRUE

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_url`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

browseURL(app$get_url())

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_window_size`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

app$get_window_size()
#> $width
#> [1] 992
#>
#> $height
#> [1] 1323

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$set_window_size`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
# Set init window size
app <- AppDriver$new(app_path, height = 1400, width = 1000)

app$get_window_size()
#> $width
#> [1] 1000
#>
#> $height
#> [1] 1400

# Manually set the window size
app$set_window_size(height = 1080, width = 1920)
app$get_window_size()
#> $width
#> [1] 1920
#>
#> $height
#> [1] 1080

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_chromote_session`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

b <- app$get_chromote_session()
b$Runtime$evaluate("1 + 1")
#> $result
#> $result$type
#> [1] "number"
#>
#> $result$value
#> [1] 2
#>
#> $result$description
#> [1] "2"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_variant`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")

app <- AppDriver$new(app_path)

app$get_variant()
#> NULL

app <- AppDriver$new(app_path, variant = platform_variant())
app$get_variant()
#> [1] "mac-4.1"

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$get_logs`
## ------------------------------------------------

## Not run: 
app1 <- AppDriver$new(system.file("examples/01_hello", package = "shiny"))

app1$get_logs()
#> {shinytest2} R  info   10:00:28.86 Start AppDriver initialization
#> {shinytest2} R  info   10:00:28.86 Starting Shiny app
#> {shinytest2} R  info   10:00:29.76 Creating new ChromoteSession
#> {shinytest2} R  info   10:00:30.56 Navigating to Shiny app
#> {shinytest2} R  info   10:00:30.70 Injecting shiny-tracer.js
#> {chromote}   JS info   10:00:30.75 shinytest2; jQuery found
#> {chromote}   JS info   10:00:30.77 shinytest2; Waiting for shiny session to connect
#> {chromote}   JS info   10:00:30.77 shinytest2; Loaded
#> {shinytest2} R  info   10:00:30.77 Waiting for Shiny to become ready
#> {chromote}   JS info   10:00:30.90 shinytest2; Connected
#> {chromote}   JS info   10:00:30.95 shinytest2; shiny:busy
#> {shinytest2} R  info   10:00:30.98 Waiting for Shiny to become idle for 200ms within 15000ms
#> {chromote}   JS info   10:00:30.98 shinytest2; Waiting for Shiny to be stable
#> {chromote}   JS info   10:00:31.37 shinytest2; shiny:idle
#> {chromote}   JS info   10:00:31.38 shinytest2; shiny:value distPlot
#> {chromote}   JS info   10:00:31.57 shinytest2; Shiny has been idle for 200ms
#> {shinytest2} R  info   10:00:31.57 Shiny app started
#> {shiny}      R  stderr ----------- Loading required package: shiny
#> {shiny}      R  stderr ----------- Running application in test mode.
#> {shiny}      R  stderr -----------
#> {shiny}      R  stderr ----------- Listening on http://127.0.0.1:4679


# To capture all websocket traffic, set `options = list(shiny.trace = TRUE)`
app2 <- AppDriver$new(
  system.file("examples/01_hello", package = "shiny"),
  options = list(shiny.trace = TRUE)
)

app2$get_logs()
## (All WebSocket messages have been replaced with `WEBSOCKET_MSG` in example below)
#> {shinytest2} R  info      10:01:57.49 Start AppDriver initialization
#> {shinytest2} R  info      10:01:57.50 Starting Shiny app
#> {shinytest2} R  info      10:01:58.20 Creating new ChromoteSession
#> {shinytest2} R  info      10:01:58.35 Navigating to Shiny app
#> {shinytest2} R  info      10:01:58.47 Injecting shiny-tracer.js
#> {chromote}   JS info      10:01:58.49 shinytest2; jQuery not found
#> {chromote}   JS info      10:01:58.49 shinytest2; Loaded
#> {shinytest2} R  info      10:01:58.50 Waiting for Shiny to become ready
#> {chromote}   JS info      10:01:58.55 shinytest2; jQuery found
#> {chromote}   JS info      10:01:58.55 shinytest2; Waiting for shiny session to connect
#> {chromote}   JS websocket 10:01:58.64 send WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.67 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.67 shinytest2; Connected
#> {chromote}   JS websocket 10:01:58.71 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.72 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.72 shinytest2; shiny:busy
#> {chromote}   JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {shinytest2} R  info      10:01:58.75 Waiting for Shiny to become idle for 200ms within 15000ms
#> {chromote}   JS info      10:01:58.75 shinytest2; Waiting for Shiny to be stable
#> {chromote}   JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote}   JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.81 shinytest2; shiny:idle
#> {chromote}   JS websocket 10:01:58.82 recv WEBSOCKET_MSG
#> {chromote}   JS info      10:01:58.82 shinytest2; shiny:value distPlot
#> {chromote}   JS info      10:01:59.01 shinytest2; Shiny has been idle for 200ms
#> {shinytest2} R  info      10:01:59.01 Shiny app started
#> {shiny}      R  stderr    ----------- Loading required package: shiny
#> {shiny}      R  stderr    ----------- Running application in test mode.
#> {shiny}      R  stderr    -----------
#> {shiny}      R  stderr    ----------- Listening on http://127.0.0.1:4560
#> {shiny}      R  stderr    ----------- SEND {"config":{"workerId":"","sessionId"|truncated
#> {shiny}      R  stderr    ----------- RECV {"method":"init","data":{"bins":30,|truncated
#> {shiny}      R  stderr    ----------- SEND {"custom":{"showcase-src":{"srcref":|truncated
#> {shiny}      R  stderr    ----------- SEND {"busy":"busy"}
#> {shiny}      R  stderr    ----------- SEND {"custom":{"showcase-src":{"srcref":|truncated
#> {shiny}      R  stderr    ----------- SEND {"recalculating":{"name":"distPlot",|truncated
#> {shiny}      R  stderr    ----------- SEND {"recalculating":{"name":"distPlot",|truncated
#> {shiny}      R  stderr    ----------- SEND {"busy":"idle"}
#> {shiny}      R  stderr    ----------- SEND {"errors":{},"values":{"distPlot":|truncated

# The log that is returned is a `data.frame()`.
log <- app2$get_logs()
tibble::glimpse(log)
#> Rows: 43
#> Columns: 5
#> $ workerid  <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, …
#> $ timestamp <dttm> 2022-09-19 10:01:57, 2022-09-19 10:01:57, 2022-09-19 10:01:58, 2022…
#> $ location  <chr> "shinytest2", "shinytest2", "shinytest2", "shinytest2", "shinytest2"…
#> $ level     <chr> "info", "info", "info", "info", "info", "info", "info", "info", "inf…
#> $ message   <chr> "Start AppDriver initialization", "Starting Shiny app", "Creating ne…
#> $ workerid  <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, …
#> $ timestamp <dttm> 2022-03-16 11:09:57, 2022-03-16 11:09:57, 2022-03-16 11:09:…
#> $ location  <chr> "shinytest2", "shinytest2", "shinytest2", "shinytest2", "shi…
#> $ level     <chr> "info", "info", "info", "info", "info", "info", "info", "inf…
#> $ message   <chr> "Start AppDriver initialization", "Starting Shiny app", "Cre…

# It may be filtered to find desired logs
subset(log, level == "websocket")
## (All WebSocket messages have been replaced with `WEBSOCKET_MSG` in example below)
#> {chromote} JS websocket 10:01:58.64 send WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.67 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.71 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.72 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.73 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.81 recv WEBSOCKET_MSG
#> {chromote} JS websocket 10:01:58.82 recv WEBSOCKET_MSG

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$log_message`
## ------------------------------------------------

## Not run: 
app_path <- system.file("examples/01_hello", package = "shiny")
app <- AppDriver$new(app_path)

app$log_message("Setting bins to smaller value")
app$set_inputs(bins = 10)
app$get_logs()

## End(Not run)

## ------------------------------------------------
## Method `AppDriver$stop`
## ------------------------------------------------

## Not run: 
rlang::check_installed("reactlog")

library(shiny)
shiny_app <- shinyApp(
  ui = fluidPage(
    actionButton("button", "Stop app and return Reactlog"),
    "Click count:", textOutput("count")
  ),
  server = function(input, output) {
    output$count <- renderText({ input$button })
    observe({
      req(input$button)
      stopApp(shiny::reactlog())
    })
  }
)

app <- AppDriver$new(
  shiny_app,
  # Enable reactlog in background R session
  options = list(shiny.reactlog = TRUE)
)

app$click("button")
rlog <- app$stop()
str(head(rlog, 2))
#> List of 2
#> $ :List of 7
#> ..$ action : chr "define"
#> ..$ reactId: chr "r3"
#> ..$ label  : chr "Theme Counter"
#> ..$ type   : chr "reactiveVal"
#> ..$ value  : chr " num 0"
#> ..$ session: chr "bdc7417f2fc8c84fc05c9518e36fdc44"
#> ..$ time   : num 1.65e+09
#> $ :List of 7
#> ..$ action : chr "define"
#> ..$ reactId: chr "r4"
#> ..$ label  : chr "output$count"
#> .. ..- attr(*, "srcref")= int [1:6] 7 32 7 45 32 45
#> .. ..- attr(*, "srcfile")= chr ""
#> ..$ type   : chr "observer"
#> ..$ value  : chr " NULL"
#> ..$ session: chr "bdc7417f2fc8c84fc05c9518e36fdc44"
#> ..$ time   : num 1.65e+09

## End(Not run)

Compare screenshots given threshold value

Description

chromote can sometimes produce screenshot images with non-deterministic (yet close) color values. This can happen in locations such as rounded corners of divs or textareas.

Usage

compare_screenshot_threshold(
  old,
  new,
  ...,
  threshold = getOption("shinytest2.compare_screenshot.threshold", NULL),
  kernel_size = getOption("shinytest2.compare_screenshot.kernel_size", 5),
  quiet = FALSE
)

screenshot_max_difference(
  old,
  new = missing_arg(),
  ...,
  kernel_size = getOption("shinytest2.compare_screenshot.kernel_size", 5)
)

Arguments

Details

These differences make comparing screenshots impractical using traditional expectation methods as false-positives are produced often over time. To mitigate this, we can use a fuzzy matching algorithm that can tolerate small regional differences throughout the image. If the local changes found are larger than the threshold, then the images are determined to be different. Both the screenshot difference threshold and the size of the kernel (kernel_size) can be set to tune the false positive rate.

Functions

• compare_screenshot_threshold(): Compares two images and allows for a threshold difference of so many units in each RGBA color channel.

  It is suggested to use this method with AppDriver⁠$expect_screenshot(threshold=, kernel_size=)⁠ to make expectations on screenshots given particular threshold and kernel_size values.

• screenshot_max_difference(): Finds the difference between two screenshots.

  This value can be used in compare_screenshot_threshold(threshold=). It is recommended that the value used for compare_screenshot_threshold(threshold=) is larger than the immediate max difference found. This allows for random fluctuations when rounding sub pixels.

  If new is missing, it will use the file value of old (FILE.png) and default to FILE.new.png

Algorithm for the difference between two screenshots

1. First the two images are compared using testthat::compare_file_binary(). If the files are identical, return TRUE that the screenshot images are the same.

2. If threshold is NULL, return FALSE as the convolution will not occur.

3. Prepare the screenshot difference matrix by reading the RGBA channels of each image and find their respective absolute differences

4. Sum the screenshot difference matrix channels at each pixel location

5. Perform a convolution using a small square kernel matrix that is kernel_size big and filled with 1s.

6. Find the largest value in the resulting convolution matrix.

7. If this max convolution value is larger than threshold, return FALSE, images are different.

8. Otherwise, return TRUE, images are the same.

Examples

img_folder <- system.file("example/imgs/", package = "shinytest2")
slider_old <- fs::path(img_folder, "slider-old.png")
slider_new <- fs::path(img_folder, "slider-new.png")

# Can you see the differences between these two images?
showimage::show_image(slider_old)
showimage::show_image(slider_new)

# You might have caught the difference between the two images!
slider_diff <- fs::path(img_folder, "slider-diff.png")
showimage::show_image(slider_diff)

# Let's find the difference between the two images
screenshot_max_difference(slider_old, slider_new)
# ~ 28

# Using different threshold values...
compare_screenshot_threshold(slider_old, slider_new, threshold = NULL)
#> FALSE # Images are not identical
compare_screenshot_threshold(slider_old, slider_new, threshold = 25)
#> FALSE # Images are more different than 25 units
compare_screenshot_threshold(slider_old, slider_new, threshold = 30)
#> TRUE # Images are not as different as 30 units

#########################

# Now let's look at two fairly similar images
bookmark_old <- fs::path(img_folder, "bookmark-old.png")
bookmark_new <- fs::path(img_folder, "bookmark-new.png")

# Can you see the difference between these two images?
# (Hint: Focused corners)
showimage::show_image(bookmark_old)
showimage::show_image(bookmark_new)

# Can you find the red pixels showing the differences?
# Hint: Look in the corners of the focused text
bookmark_diff <- fs::path(img_folder, "bookmark-diff.png")
showimage::show_image(bookmark_diff)

# Let's find the difference between the two images
screenshot_max_difference(bookmark_old, bookmark_new)
# ~ 0.25

# Using different threshold values...
compare_screenshot_threshold(bookmark_old, bookmark_new, threshold = NULL)
#> FALSE # Images are not identical
compare_screenshot_threshold(bookmark_old, bookmark_new, threshold = 5)
#> TRUE # Images are not as different than 5 units

Load the Shiny application's support environment

Description

Executes all ./R files and global.R into the current environment. This is useful when wanting access to functions or values created in the ./R folder for testing purposes.

Usage

load_app_env(
  app_dir = "../../",
  renv = rlang::caller_env(),
  globalrenv = rlang::caller_env()
)

Arguments

Details

Loading these files is not automatically performed by test_app() and must be called in ./tests/testthat/setup-shinytest2.R if access to support file objects is desired.

See Also

use_shinytest2() for creating a testing setup file that loads your Shiny app support environment into the testing environment.

Migrate shinytest tests

Description

This function will migrate standard shinytest test files to the new shinytest2 + testthat ed 3 snapshot format.

Usage

migrate_from_shinytest(
  app_dir,
  ...,
  clean = TRUE,
  include_expect_screenshot = missing_arg(),
  quiet = FALSE
)

Arguments

Details

shinytest file contents will be traversed and converted to the new shinytest2 format. If the shinytest code can not be directly seen in the code, then it will not be converted.

Value

Invisible TRUE

Platform specific variant

Description

Returns a string to be used within testthat's' snapshot testing. Currently, the Operating System and R Version (major, minor, no patch version) are returned.

Usage

platform_variant(..., os_name = TRUE, r_version = TRUE)

Arguments

Details

If more information is needed in the future to distinguish standard testing environments, this function will be updated accordingly.

See Also

testthat::test_dir()

Launch test event recorder for a Shiny app

Description

Once a recording is completed, it will create or append a new shinytest2 test to the testthat test_file.

Usage

record_test(
  app = ".",
  ...,
  name = NULL,
  seed = NULL,
  load_timeout = NULL,
  shiny_args = list(),
  test_file = "test-shinytest2.R",
  open_test_file = rlang::is_interactive(),
  allow_no_input_binding = NULL,
  record_screen_size = TRUE,
  run_test = TRUE
)

Arguments

Uploading files

Files that are uploaded to your Shiny app must be located somewhere within the tests/testthat subdirectory or available via system.file().

Files that are uploaded during recording that do not have a valid path will have a warning inserted into the code. Please fix the file path by moving the file to the tests/testthat subdirectory or by using system.file(). After fixing the path, remove the line of warning code.

See Also

test_app()

Examples

## Not run: 
record_test("path/to/app")

## End(Not run)

Register an input processor for the test recorder

Description

register_input_processor() registers an input processor which will be used by the test recorder. The input processor function should take one parameter, value, and return a string of R code which returns the desired value.

get_input_processors() returns a named list of all registered input processor functions.

Usage

register_input_processor(input_type, processor)

get_input_processors()

Arguments

Test Shiny applications with testthat

Description

This is a helper method that wraps around testthat::test_dir() to test your Shiny application or Shiny runtime document. This is similar to how testthat::test_check() tests your R package but for your app.

Usage

test_app(
  app_dir = missing_arg(),
  ...,
  name = missing_arg(),
  check_setup = TRUE,
  reporter = testthat::get_reporter(),
  stop_on_failure = missing_arg()
)

Arguments

Details

Example usage:

## Interactive usage
# Test Shiny app in current working directory
shinytest2::test_app()

# Test Shiny app in another directory
path_to_app <- "path/to/app"
shinytest2::test_app(path_to_app)

## File: ./tests/testthat.R
# Will find Shiny app in "../"
shinytest2::test_app()

## File: ./tests/testthat/test-shinytest2.R
# Test a shiny application within your own {testthat} code
test_that("Testing a Shiny app in a package", {
  shinytest2::test_app(path_to_app)
})

Uploading files

When testing an application, all non-temp files that are uploaded should be located in the ./tests/testthat directory. This allows for tests to be more portable and self contained.

When recording a test with record_test(), for every uploaded file that is located outside of ./tests/testthat, a warning will be thrown. Once the file path has be fixed, you may remove the warning statement.

Different ways to test

test_app() is an opinionated testing function that will only execute testthat tests in the ./tests/testthat folder. If (for some rare reason) you have other non-testthat tests to execute, you can call shiny::runTests(). This method will generically run all test runners and their associated tests.

# Execute a single Shiny app's {testthat} file such as `./tests/testthat/test-shinytest2.R`
test_app(filter = "shinytest2")

# Execute all {testthat} tests
test_app()

# Execute all tests for all test runners
shiny::runTests()

See Also

• record_test() to create tests to record against your Shiny application.

• testthat::snapshot_review() and testthat::snapshot_accept() if you want to compare or update snapshots after testing.

• load_app_env() to load the Shiny application's helper files. This is only necessary if you want access to the values while testing.

Use shinytest2 with your Shiny application

Description

Use shinytest2 with your Shiny application

Usage

use_shinytest2(
  app_dir = ".",
  runner = missing_arg(),
  setup = missing_arg(),
  ignore = missing_arg(),
  package = missing_arg(),
  ...,
  quiet = FALSE,
  overwrite = FALSE
)

use_shinytest2_test(
  app_dir = ".",
  open = rlang::is_interactive(),
  quiet = FALSE,
  overwrite = FALSE
)

Arguments

Functions

• use_shinytest2(): This usethis-style method initializes many different useful features when using shinytest2:

  • runner: Creates a shinytest2 test runner at ./tests/testthat.R. This file will contain a call to test_app().

  • setup: Creates ./tests/testthat/setup-shinytest2.R to add your Shiny ./R objects and functions into the testing environment. This file will run before testing begins.

  • ignore: Add an entry to ./Rbuildignore (if it exists) and .gitignore to ignore new debug screenshots. (⁠*_.new.png⁠)

  • package: Adds shinytest to the Suggests packages in the DESCRIPTION file (if it exists).

  If any of these values are not missing, the remaining missing values will be set to FALSE. This allows use_shinytest2() to add more flags in future versions without opting into all changes inadvertently.

• use_shinytest2_test(): Creates a test file called ./tests/testthat/test-shinytest2.R. By default, this file's template test will initialize your Shiny application and expect the initial values.

  This method will also set up a test runner if it does not exist.

Examples

# Set up shinytest2 testing configs
## Not run: use_shinytest2()
# Set up a shinytest2 test
## Not run: use_shinytest2_test()