Espresso

• Espresso - used to write concise, beautiful, and reliable Android UI tests.

• Espresso tests state expectations and interactions clearly without messy implementation details getting in the way.

  • Target audience - developers, who believe that automated testing is an integral part of the development lifecycle.

  • Synchronization capabilities
    • Each time your test invokes onView(), Espresso waits to perform the corresponding UI action or assertion until the following synchronization conditions are met:
      • message queue is empty
      • no instances of AsyncTask currently executing a task
      • all developer-defined idling resources are idle
  • Packages
    • espresso-core - contains core and basic View matchers, actions, and assertions
    • espresso-web - contains resources for WebView support
    • espresso-idling-resource - Espresso’s mechanism for synchronization with background jobs
    • espresso-contrib - external contributions that contain DatePicker, RecyclerView and Drawer actions, accessibility checks, and CountingIdlingResource
    • espresso-intents - extension to validate and stub intents for hermetic testing
    • espresso-remote - location of Espresso’s multi-process functionality

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Create UI tests with Espresso Test Recorder:

• Espresso Test Recorder tool - lets you create UI tests for your app without writing any test code. Takes the saved recording and automatically generates a corresponding UI test that you can run to test your app. Writes tests based on the Espresso Testing framework, an API in AndroidX Test.
• Turn off animations on your test device
  • Before using Espresso Test Recorder, make sure you turn off animations on your test device to prevent unexpected results. Follow the “Set Up Espresso” instructions on the Testing UI for a Single App page, but note that you do not need to manually set a dependency reference.
  • Record an Espresso test
    • Espresso tests consist of two primary components:
      • UI interactions - tap and type actions that a person may use to interact with your app.
      • Assertions - verify the existence or contents of visual elements on the screen.
  • Record UI interactions
    • To start recording a test - click Run > Record Espresso Test, choose the device on which you want to record the test in the Select Deployment Target window, and then Espresso Test Recorder triggers a build of your project, and the app must install and launch. The Record Your Test window appears after the app launches, and then you can interact with it.
  • Add assertions to verify UI elements
    • Three main types - text is, exists, and does not exist
    • To add assertions - click Add Assertions, to select a View element click on the element in the screenshot or use the first drop-down menu in the Edit assertion box at the bottom of the window, elect the assertion you want to use from the second drop-down menu in the Edit assertion box, and then click Save and Add Another to create another assertion or click Save Assertion to close the assertion panels.
  • Save a recording - click Complete Recording, pick a test class name for your test window appears, use the Test class name text field if you want to change the suggested name, and click Save.
  • Run an Espresso test locally - use the Project window on the left side of the Android Studio IDE, open the desired app module folder and navigate to the test you want to run, right-click on the test and click Run ‘testName’, and in the Select Deployment Target window, choose the device on which you want to run the test.