Test Shiny applications with testthat

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(),
  reporter = testthat::get_reporter(),
  stop_on_failure = missing_arg(),
  check_setup = deprecated(),
  quiet = FALSE
)

Arguments

app_dir

The base directory for the Shiny application.

• If app_dir is missing and test_app() is called within the ./tests/testthat.R file, the parent directory ("../") is used.

• Otherwise, the default path of "." is used.

...

Parameters passed to testthat::test_dir()

name

Name to display in the middle of the test name. This value is only used when calling test_app() inside of testhat test. The final testing context will have the format of "{test_context} - {name} - {app_test_context}".

reporter

Reporter to pass through to testthat::test_dir().

stop_on_failure

If missing, the default value of TRUE will be used. However, if missing and currently testing, FALSE will be used to seamlessly integrate the app reporter to reporter.

check_setup

Deprecated. Parameter ignored.

quiet

If TRUE, suppresses deprecation warnings when called within testthat tests.

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", {
  app <- shinytest2::AppDriver$new(path_to_app)
  # Perform tests with `app`...
})

When testing within a package, it is recommended to not call test_app(), but instead test your applications within your own testthat tests. This allows for more flexibility and control over how your applications are tested while your current package's testthat infrastructure. See the Use Package vignette for more details.

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.

• local_app_support() / with_app_support() to load the Shiny application's helper files into respective environments. These methods are useful for within package testing as they have fine tune control over when the support environment is loaded.

• load_app_support() to load the Shiny application's helper files into the calling environment. This method is useful for non-package based Shiny applications where the support environment should be available in every test file.