[SOLVED] JUnit tests fail with "Emtpy test suite" and exception from LoggerFactory IntelliJ 2017.2.5

Hi,

having tried a lot of suggestions from other posts here and around the web but ran out of ideas.

I upgraded to IntelliJ 2017.2.5 and the JUnit tests won't start since this upgrade. I think that it has something to do with JUnit5. I added the following Maven dependency:

<dependency>
    <groupId>org.junit.jupiter</groupId>
    <artifactId>junit-jupiter-api</artifactId>
    <version>5.0.0-M4</version>
    <scope>test</scope>
</dependency>

The error log is:

Exception in thread "main" java.lang.NoClassDefFoundError: org/junit/platform/commons/logging/LoggerFactory
    at org.junit.platform.launcher.core.DefaultLauncher.<clinit>(DefaultLauncher.java:44)
    at org.junit.platform.launcher.core.LauncherFactory.create(LauncherFactory.java:59)
    at com.intellij.junit5.JUnit5IdeaTestRunner.createListeners(JUnit5IdeaTestRunner.java:39)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:45)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.ClassNotFoundException: org.junit.platform.commons.logging.LoggerFactory
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 6 more

I don't see anything special in my test classes either (a little bit stripped down to the basics)

package worker.specialclasses;

import basicvalues.Constants;
import jdk.nashorn.internal.ir.annotations.Ignore;
import org.junit.jupiter.api.AfterEach;
import org.junit.jupiter.api.BeforeAll;
import org.junit.jupiter.api.Test;
import worker.MyClass;

import java.io.IOException;
import java.math.BigDecimal;

import static org.junit.jupiter.api.Assertions.*;


class MySpecialClassTest {
    private static MySpecialClass mMySpecialClassInstance;

    @BeforeAll
    static void setUp() throws Exception {
        mMySpecialClassInstance = MySpecialClass.getInstance();
    }

    @AfterEach
    @Ignore
    void tearDown() {
    }

    @Test
    void getInstance() throws Exception {
        assertNotNull(mMySpecialClassInstance);
    }

    @Test
    void getSpecialClass() {
        assertNotNull(mMySpecialClassInstance.getSpecialClass());
    }

    @Test
    void getApiUsername() {
        assertEquals(Constants.USERNAME, mMySpecialClassInstance.getApiUsername());
    }


}

If you have any ideas, I'd greatly appreciate!

Thank you in advance and kind regards