> For the complete documentation index, see [llms.txt](https://cover-docs.diffblue.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cover-docs.diffblue.com/features/cover-cli/writing-tests/test-validation.md).

# Test validation

After tests have been generated, Cover validates newly created tests by invoking the test phase of your build tool (`Maven`, `Gradle`). Cover will then remove any created tests that fail compilation or execution.

* Existing unit tests must compile **and** pass (`mvn test`, `gradle test`) before `dcover create` is invoked.
* If unvalidated JUnit 5 tests (those which fail to compile or run successfully) are generated by `dcover create`, please confirm that running `mvn test` actually executes your unit tests. JUnit 5 requires at minimum Maven Surefire v2.22.0 to work, and if an older version is present `mvn test` will pass without executing any tests. You can specify the Surefire Plugin version in your POM using:

  ```xml
  <build>
    <plugins>
      <plugin>
          <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.2</version>
      </plugin>
    </plugins>
  </build>
  ```
* When running `mvn test`, `dcover` can disable known style checking plugins (`checkstyle`, `spring-javaformat`) by using the `--ignore-stylechecks` argument.
* Test validation is bypassed if a build tool (`Maven`, `Gradle`) is not detected from your environment. In that case it is possible that some created tests may fail compilation or execution.

## Test Validation and user-specified system properties

The `-D` or `--define` option allows you to pass additional system properties to `dcover` for test creation and execution.

Any created tests *may* depend upon these user-specified system properties and *may not* execute successfully without them.

During test validation `dcover` will forward user-specified system properties to your build tool, be that `Maven` or `Gradle`.

`Maven` is able to utilize these forwarded properties when executing tests for test validation. No configuration is required.

However `Gradle` does not forward system properties to executed tests and will require further configuration to do so. In such a case test validation is likely to fail out-of-the-box without changes to your build script (`build.gradle` or `build.gradle.kts`).

In any case, for `Maven` and `Gradle` you will need to configure test execution in your build script to supply these same user-specified system properties when executing those tests outside `dcover`.

For more details about build tool configuration with system properties, see the [Maven](/features/cover-cli/project-configuration/compiling-your-project/building-a-maven-project.md#maven-and-user-specified-system-properties) and [Gradle](/features/cover-cli/project-configuration/compiling-your-project/building-a-gradle-project.md#gradle-and-user-specified-system-properties) topics.