You can open this sample in an IDE that supports Gradle.

This sample shows how to aggregate test results across multiple Java subprojects. The test-report-aggregation plugin provides this ability via a standalone project used to specify which subprojects to include for aggregation.

The project in this example contains three "code" subprojects: application, list and utilities. All three projects apply the java plugin, and application consumes both list and utilities via its implementation configuration. A fourth subproject test-results is the standalone utility project used to collect the aggregated test results.

The Test Report Aggregation plugin does not currently work with the com.android.application plugin.
test-results/build.gradle.kts
plugins {
    base
    id("test-report-aggregation")
}

dependencies {
    testReportAggregation(project(":application")) (1)
}

reporting {
    reports {
        val testAggregateTestReport by creating(AggregateTestReport::class) { (2)
            testType = TestSuiteType.UNIT_TEST
        }
    }
}

tasks.check {
    dependsOn(tasks.named<TestReport>("testAggregateTestReport")) (3)
}
test-results/build.gradle
plugins {
    id 'base'
    id 'test-report-aggregation'
}

dependencies {
    testReportAggregation project(':application') (1)
}

reporting {
    reports {
        testAggregateTestReport(AggregateTestReport) { (2)
            testType = TestSuiteType.UNIT_TEST
        }
    }
}

tasks.named('check') {
    dependsOn tasks.named('testAggregateTestReport', TestReport) (3)
}

The standalone project applies test-report-aggregation, but requires additional configuration if the jvm-test-suite plugin is not also present (it will be automatically applied by the java plugin).

In this scenario, two additional pieces of setup are necessary:

1 Declare dependencies using the testReportAggregation configuration
2 Define a report of type AggregateTestReport which collects test data from unit test suites
3 Optional: make aggregate test report generation part of the 'check' lifecycle phase

The report aggregation logic does not automatically inspect all subprojects for test results to aggregate. Instead, the direct and transitive project dependencies of the testReportAggregation configuration are selected for potential aggregation.

The user must also declare one or more reports of type AggregateTestReport. Each report instance specifies a testType property, used to match the test suite producing the test data. A TestReport task is synthesized for each user-defined report and performs the aggregation. Invoking this task will cause tests to be executed in the dependent projects of the testReportAggregation configuration.

Run the tests and generate the report:

$ ./gradlew testAggregateTestReport

BUILD SUCCESSFUL
24 actionable tasks: 24 executed

The aggregated HTML report can now be found under test-results/build/reports/tests/unit-tests/aggregated-results.

For more information, see Testing in Java project chapter.