diff --git a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/UITestCaseWithProject.java b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/UITestCaseWithProject.java
index 15db270316e..c2423603494 100644
--- a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/UITestCaseWithProject.java
+++ b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/UITestCaseWithProject.java
@@ -39,7 +39,7 @@ import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.core.runtime.NullProgressMonitor;
 import org.eclipse.core.runtime.Path;
 
-public class UITestCaseWithProject extends BaseUITestCase {
+public abstract class UITestCaseWithProject extends BaseUITestCase {
 	ArrayList<File> tempFiles = new ArrayList<>();
 	protected File tmpDir;
 	protected ICProject cproject;
diff --git a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTestBase.java b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTestBase.java
index 2044c83fb00..26a37cde9a2 100644
--- a/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTestBase.java
+++ b/core/org.eclipse.cdt.ui.tests/ui/org/eclipse/cdt/ui/tests/text/contentassist2/CompletionTestBase.java
@@ -19,7 +19,7 @@ import org.eclipse.core.resources.IProject;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.jface.text.contentassist.ICompletionProposal;
 
-public class CompletionTestBase extends AbstractContentAssistTest {
+public abstract class CompletionTestBase extends AbstractContentAssistTest {
 	private static final String HEADER_FILE_NAME = "CompletionTest.h";
 	private static final String SOURCE_FILE_NAME = "CompletionTest.cpp";
 	private static final String CURSOR_LOCATION_TAG = "/*cursor*/";