Gradle test task in JUnit - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the Gradle test task?

The Gradle test task runs the unit tests in a project, typically using frameworks like JUnit. It compiles the test code and executes tests to check if the code works as expected.

intermediate

How do you run only tests with a specific name pattern using the Gradle test task?

You can configure the test task in build.gradle with filter { includeTestsMatching 'pattern' } to run only tests matching that pattern.

beginner

What file does Gradle use to configure the test task?

Gradle uses the build.gradle file to configure the test task and other build settings.

beginner

How can you generate a test report after running the Gradle test task?

Gradle automatically generates a test report in build/reports/tests/test/index.html after running the test task. You can open this file in a browser to see test results.

intermediate

What is the default testing framework used by Gradle's test task when using JUnit?

Gradle supports JUnit 4 and JUnit 5 by default. You need to add the correct dependencies in build.gradle to use the desired JUnit version.

What command runs the tests in a Gradle project?

A gradle test

B gradle build

C gradle run

D gradle clean

The gradle test command runs the unit tests in the project.

Where does Gradle place the test reports by default?

A reports/tests/index.html

B src/test/reports/index.html

C build/test-results/index.html

D build/reports/tests/test/index.html

Gradle generates test reports in build/reports/tests/test/index.html by default.

How can you include only tests matching a pattern in Gradle?

A filter { includeTestsMatching 'pattern' }

B includeTests('pattern')

C testPattern('pattern')

D onlyTests('pattern')

You use filter { includeTestsMatching 'pattern' } inside the test task configuration.

Which file configures the Gradle test task?

A test.gradle

B build.gradle

C gradle.properties

D settings.gradle

The build.gradle file is used to configure the test task.

To use JUnit 5 in Gradle, what must you do?

A Use a special Gradle plugin

B Nothing, JUnit 5 is included by default

C Add JUnit 5 dependencies in build.gradle

D Rename test files to end with J5

You must add the JUnit 5 dependencies explicitly in build.gradle to use it.

Explain how the Gradle test task works and how you can customize which tests run.

Think about running tests and filtering them.

Describe where Gradle stores test reports and how you can view them.

Reports are saved as HTML files.

Practice

1. What is the primary purpose of the Gradle test task in a JUnit project?

easy

A. To compile the Java source code into bytecode

B. To run automated tests and check if the code works correctly

C. To deploy the application to a server

D. To clean the build directory before building

Solution

1. Step 1: Understand the Gradle test task role

   The test task in Gradle is designed to run automated tests, such as those written with JUnit, to verify code correctness.

2. Step 2: Differentiate from other Gradle tasks

   Tasks like compileJava compile code, clean removes build files, and deployment is separate. Only test runs tests.

3. Final Answer:

   To run automated tests and check if the code works correctly -> Option B

4. Quick Check:

   Gradle test = run tests [OK]

Hint: Remember: 'gradle test' runs your tests [OK]

Common Mistakes:

• Confusing test task with compile or clean tasks
• Thinking test deploys the app
• Assuming test cleans build files

2. Which of the following is the correct command to run JUnit tests using Gradle from the terminal?

easy

A. gradle checkTests

B. gradle runTests

C. gradle executeTests

D. gradle test

Solution

1. Step 1: Recall the standard Gradle test command

   The official Gradle command to run tests is gradle test. This triggers the test task which runs JUnit tests.

2. Step 2: Verify other options are invalid

   Commands like runTests, executeTests, and checkTests are not standard Gradle commands and will cause errors.

3. Final Answer:

   gradle test -> Option D

4. Quick Check:

   Run tests with gradle test [OK]

Hint: Use exactly 'gradle test' to run tests [OK]

Common Mistakes:

• Adding extra words like run or execute
• Using non-existent Gradle commands
• Confusing test with build or run

3. Given this snippet in build.gradle:

test {
    useJUnitPlatform()
    testLogging {
        events "passed", "failed"
    }
}

What will be the output when you run gradle test and all tests pass?

medium

A. Both passed and failed test events are shown in the console

B. Only failed tests are shown in the output

C. No output because logging is disabled

D. Only passed tests are shown, failed tests are ignored

Solution

1. Step 1: Understand the testLogging configuration

   The testLogging block with events "passed", "failed" means Gradle will log passed and failed test events when they occur.

2. Step 2: Predict output when all tests pass

   Since all tests pass, passed test events are shown. Failed events do not occur, so they are not shown. Therefore, only passed test events appear in the console.

3. Final Answer:

   Both passed and failed test events are shown in the console -> Option A

4. Quick Check:

   Passed and failed events configured to show; failed events absent if none fail [OK]

Hint: Check testLogging events to know what shows [OK]

Common Mistakes:

• Assuming no output if tests pass
• Thinking only failed tests show by default
• Ignoring testLogging configuration

4. You added this to your build.gradle:

test {
    useJUnitPlatform()
    testLogging {
        events "passed", "failed"
    }
    include '**/MyTests.java'
}

But running gradle test runs no tests. What is the likely problem?

medium

A. The include pattern should use forward slashes and match class files, not source files

B. You forgot to add useJUnit() instead of useJUnitPlatform()

C. The testLogging block disables test execution

D. Gradle test task cannot filter tests by include patterns

Solution

1. Step 1: Understand the include pattern usage

   The include pattern filters test classes by their compiled class file names, not source files. It should match **/MyTests.class or use package style with forward slashes.

2. Step 2: Identify why no tests run

   Using **/MyTests.java does not match any compiled test classes, so no tests run.

3. Final Answer:

   The include pattern should use forward slashes and match class files, not source files -> Option A

4. Quick Check:

   Include matches class files, not .java [OK]

Hint: Include filters need class file patterns, not source files [OK]

Common Mistakes:

• Using .java instead of .class in include patterns
• Confusing useJUnitPlatform with test execution
• Thinking testLogging disables tests

5. You want to customize the Gradle test task to run only tests tagged with @Tag("fast") in JUnit 5. Which build.gradle snippet correctly configures this?

hard

A. test {
includeTags 'fast'
}

B. test {
useJUnitPlatform()
includeTags 'fast'
}

C. test {
useJUnitPlatform {
includeTags 'fast'
}
}

D. test {
useJUnitPlatform()
testLogging {
includeTags 'fast'
}
}

Solution

1. Step 1: Recall how to filter tests by tags in Gradle

   Gradle's useJUnitPlatform accepts a configuration block where you can specify includeTags to run only tests with certain tags.

2. Step 2: Check each option for correct syntax

   test { useJUnitPlatform { includeTags 'fast' } } correctly places includeTags 'fast' inside the useJUnitPlatform block. Other options place it incorrectly or omit useJUnitPlatform.

3. Final Answer:

   test { useJUnitPlatform { includeTags 'fast' } } -> Option C

4. Quick Check:

   Tag filtering goes inside useJUnitPlatform block [OK]

Hint: Put includeTags inside useJUnitPlatform block [OK]

Common Mistakes:

• Placing includeTags outside useJUnitPlatform
• Adding includeTags inside testLogging
• Omitting useJUnitPlatform call