JUnit - run tests in a category only if specific profile is active - maven

Question

I have the following tests:
FirstUnitTest.java
SecondUnitTest.java
FirstIntegrationTest.java
SecondIntegrationTest.java
The unit tests are not marked with a category.
The two integration tests are marked with #Category(IntegrationTests.class).
I want by default to run all tests EXCEPT for the integration tests.
If, however, a profile integration-tests-only is active, i want to run ONLY the integration tests.
I naively thought the following configuration would make this work:
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<excludedGroups>com.example.IntegrationTests</excludedGroups>
</configuration>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>integration-tests-only</id>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<configuration>
<groups>com.example.IntegrationTests</groups>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
But while running the tests without a profile does exactly what I want - run only the unit tests, if I activate the integration-tests-only profile no tests run at all.
Any ideas what I'm doing wrong?

Answer 1

I assume that this happens because you include and exclude, and Maven merges the configurations and resolves to run nothing.
Consider this re-write of the config (did not run it so might have some minor issues):
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.19.1</version>
<executions>
<execution>
<id>default-test</id>
<configuration>
<skip>true</skip>
</configuration>
</execution>
<execution>
<id>unit-tests</id>
<phase>test</phase>
<goals>
<goal>test</goal>
</goals>
<configuration>
<skip>${skipUnitTests}</skip>
<excludedGroups>com.example.IntegrationTests</excludedGroups>
</configuration>
</execution>
<execution>
<id>integ-tests</id>
<phase>test</phase>
<goals>
<goal>test</goal>
</goals>
<configuration>
<skip>${skipIntegTests}</skip>
<groups>com.example.IntegrationTests</groups>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<profiles>
<profile>
<id>no-tests</id>
<properties>
<skipTests>true</skipTests>
</properties>
</profile>
<profile>
<id>unit-tests</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<properties>
<skipUnitTests>false</skipUnitTests>
<skipIntegTests>true</skipIntegTests>
</properties>
</profile>
<profile>
<id>integ-tests</id>
<properties>
<skipUnitTests>true</skipUnitTests>
<skipIntegTests>false</skipIntegTests>
</properties>
</profile>
</profiles>