Update JUnit versions in build matrix (#512 / #511)

As of today, 5.7.2 is the latest stable and 5.8.0-RC1 the latest
non-stable version.

Closes: #512
PR: #511

.github/workflows/build.yml

@@ -128,7 +128,7 @@ jobs:
     strategy:
       matrix:
         java: [ 8, 11, 16 ]
-        junit-version: [ '5.7.0', '5.7.1', '5.8.0-M1' ]
+        junit-version: [ '5.7.0', '5.7.2', '5.8.0-RC1' ]
         modular: [true, false]
         os: [ubuntu, macos, windows]
         exclude:

src/test/java/org/junitpioneer/jupiter/issue/IssueExtensionExecutionListenerTests.java

@@ -14,8 +14,8 @@
 import static org.junit.jupiter.api.Assertions.assertAll;
 import static org.junitpioneer.jupiter.issue.IssueExtensionExecutionListener.REPORT_ENTRY_KEY;
 import static org.junitpioneer.jupiter.issue.TestPlanHelper.createTestIdentifier;
+import static org.mockito.Mockito.mock;
 
-import java.util.Collections;
 import java.util.List;
 
 import org.junit.jupiter.api.Test;
@@ -35,7 +35,9 @@ public class IssueExtensionExecutionListenerTests {
 	// when debugging, be aware that the service loader also created instances of the listener;
 	// we can't use it here, because the running Jupiter instance uses it to gather test information
 	private final IssueExtensionExecutionListener executionListener = new IssueExtensionExecutionListener();
-	private final TestPlan testPlan = TestPlan.from(Collections.emptyList());
+	// TestPlan only offers a single public but internal factory method that changed in JUnit v5.8.0-RC1
+	// since we test with multiple JUnit versions, we mock this class to circumvent the problem of creating it
+	private final TestPlan testPlan = mock(TestPlan.class);
 
 	@Test
 	void noIssueTestCasesCreated() {