Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test (default-test) on project mockito-course: There are test failures.

Explanations for the error message "Failed to execute goal org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test (default-test) on project mockito-course: There are test failures":

1. Failed to execute goal: The specified goal of running tests using the Maven Surefire Plugin was unsuccessful.

2. org.apache.maven.plugins:maven-surefire-plugin:2.12.4:test: Maven tried to execute the 'test' goal using the Surefire Plugin version 2.12.4.

3. (default-test): The plugin was configured to execute the default test phase in the Maven build lifecycle.

4. on project mockito-course: This issue occurred within the Maven project named 'mockito-course'.

5. There are test failures: The execution failed because one or more tests within the project failed to pass. The Surefire Plugin detected test failures, indicating issues with the test cases written in the project.