Test Reports & Filtering

Test reports are essential for understanding the health of your project. They provide a clear summary of which tests passed, failed, or were skipped.

This insight helps developers quickly pinpoint issues, track progress, and ensure code quality. Without them, debugging would be much harder!

When you run tests with Gradle, it automatically generates an interactive HTML report every time you run your tests. This feature is enabled by default when you apply the java or java-library plugin.

These reports offer a user-friendly interface to browse test results, making analysis straightforward.

After executing your tests using the test task, Gradle places the generated report in a specific directory. Look for build/reports/tests/test/index.html.

You can open this file directly in any web browser to view a comprehensive overview of your test run. To generate one, simply run: ./gradlew test

The HTML report provides valuable details:

• Summary: Total tests, failures, and skipped tests.
• Test Classes: A list of all executed test classes.
• Individual Tests: Status and duration for each test method.
• Failure Details: Stack traces and error messages for failed tests.

This structure helps you drill down from a high-level overview to specific problem areas.

Sometimes you don't need to run all tests. Perhaps you're debugging a specific feature or re-running a failed test.

Gradle allows you to filter which tests are executed, saving time and focusing your efforts. This is done using the --tests command-line option.

To run all tests within a specific test class, provide its fully qualified name with the --tests flag.

For example, if you have a class named com.example.MyFeatureTest, you'd run:

This executes every test method inside that single class.

You can get even more granular by specifying a particular test method within a class. Append the method name to the fully qualified class name.

If com.example.MyFeatureTest has a method testSpecificCase, use:

This is extremely useful for focused debugging.

Gradle's --tests option supports wildcards (*) for more flexible matching. This allows you to run groups of tests that follow a pattern.

• *IntegrationTest: Runs all classes ending with "IntegrationTest".
• com.example.*: Runs all tests in the com.example package and its subpackages.
• *.testFailure*: Runs any method named `testFailure` (or similar) in any class.

You can apply multiple --tests options in a single command. Gradle will run any test that matches at least one of the provided patterns.

For example, to run tests from two different classes:

This provides powerful control over your test execution.

Consider a project with a test class com.myapp.services.UserServiceTest containing methods testCreateUser and testDeleteUser.

Which Gradle command will run only the testCreateUser method?

In this lesson, we explored the critical role of test reports in Gradle. You learned that:

• Gradle automatically generates detailed HTML test reports.
• These reports are found in build/reports/tests/test/index.html.
• You can filter test execution using the --tests option.
• Filters can target classes, methods, or use wildcards for flexibility.

Mastering these techniques helps you efficiently manage and debug your test suite!