Android Testing Samples

The Compose Preview Screenshot Testing tool is an experimental feature currently in development. Because it is in the alpha phase, its features and APIs are subject to substantial changes.

For official documentation and details, refer to the Compose Preview Screenshot Testing guide.

Espresso Web is an API designed for writing automated tests for hybrid applications containing one or more WebViews.

Key characteristics:

• Interaction Model: Similar to onData, WebView interactions are composed of several ViewActions. However, in Espresso Web, ViewActions are composed of Web Driver Atoms.
• Synchronization: Espresso Web handles synchronization automatically to minimize boilerplate.
• Developer Experience: It provides an Espresso-like syntax for interacting with web content within an Android application.

This repository is a collection of samples demonstrating various Android testing frameworks and techniques. Key sample categories include:

• Espresso Samples: Covers basic UI testing, custom matchers, onData() for lists, FragmentScenario, IdlingResource for synchronization, Intents (basic and advanced), multi-window testing, RecyclerView actions, screenshot capturing, and Espresso-web for WebViews.
• UiAutomator Samples: Demonstrates basic UI Automator usage for black-box testing.
• AndroidJUnitRunner Samples: Showcases test annotations, parameterized tests, and testsuite creation.
• JUnit4 Rules Samples: Demonstrates usage of ActivityTestRule, IntentsTestRule, and ServiceTestRule.

This sample demonstrates how to use Espresso Intents for hermetic inter-app testing. It utilizes a Mockito-like approach to allow for Intent verification and stubbing.

Specifically, this sample shows how to stub an Intent to simulate fetching a picture from the camera without actually leaving the main application, ensuring tests remain isolated and hermetic.

When navigating the project, use the following directory mapping:

• Application Code: src/main/java
• Instrumentation Tests: src/androidTest/java
• Local Tests: src/test/java

In this sample project, the source code is organized as follows:

• Application under test: src/main/java
• Instrumentation tests: src/androidTest/java

When exploring the Espresso Accessibility Sample, use the following directory structure to locate code:

• Application code: src/main/java
• Instrumentation Tests: src/androidTest/java
• Local Tests: src/test/java

When working with this sample, note the following directory structure:

• Application code: Located in src/main/java.
• Test source: Located in src/sharedTest/java. This single set of test sources is designed to run either locally via Robolectric or on a device/emulator via instrumented tests.

When exploring the Espresso Basic Sample, use the following directory structure to locate code:

• Application code: src/main/java
• Instrumentation Tests: src/androidTest/java
• Local Tests: src/test/java

The androidx.test.runner.AndroidJUnitRunner enables JUnit4 support for Android testing, allowing for features such as:

• Test Annotations: Standard JUnit4 style annotations.
• Parameterized Tests: Using the @Parameters annotation to run a single test with multiple different values.
• Test Suites: Grouping tests into suites such as AndroidTestSuite, UnitTestSuite, or InstrumentationTestSuite.
• Instrumentation Tests: Testing the UI of activities (e.g., CalculatorActivity) using JUnit4 style tests.