diff --git a/org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.xtend b/org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.xtend
index 0dc6aa050..25a419658 100644
--- a/org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.xtend
+++ b/org.eclipse.xtext.xtext.generator/src/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.xtend
@@ -34,7 +34,7 @@ class Junit4Fragment2 extends AbstractStubGeneratingFragment {
 					testingPackage,
 					"org.eclipse.xtext.xbase.lib"
 				)
-				exportedPackages.add(grammar.runtimeTestBasePackage)
+				exportedPackages.add(grammar.runtimeTestBasePackage+";x-internal=true")
 			]
 		}
 		if (projectConfig.eclipsePluginTest.manifest != null) {
@@ -43,7 +43,7 @@ class Junit4Fragment2 extends AbstractStubGeneratingFragment {
 					"org.eclipse.core.runtime",
 					"org.eclipse.ui.workbench;resolution:=optional"
 				)
-				exportedPackages.add(grammar.eclipsePluginTestBasePackage)
+				exportedPackages.add(grammar.eclipsePluginTestBasePackage+";x-internal=true")
 			]
 		}
 		if (projectConfig.eclipsePlugin.manifest != null) {
diff --git a/org.eclipse.xtext.xtext.generator/xtend-gen/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.java b/org.eclipse.xtext.xtext.generator/xtend-gen/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.java
index 6ef8012f0..ccc86b891 100644
--- a/org.eclipse.xtext.xtext.generator/xtend-gen/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.java
+++ b/org.eclipse.xtext.xtext.generator/xtend-gen/org/eclipse/xtext/xtext/generator/junit/Junit4Fragment2.java
@@ -74,7 +74,8 @@ public class Junit4Fragment2 extends AbstractStubGeneratingFragment {
         Set<String> _exportedPackages = it.getExportedPackages();
         Grammar _grammar = this.getGrammar();
         String _runtimeTestBasePackage = this._xtextGeneratorNaming.getRuntimeTestBasePackage(_grammar);
-        _exportedPackages.add(_runtimeTestBasePackage);
+        String _plus = (_runtimeTestBasePackage + ";x-internal=true");
+        _exportedPackages.add(_plus);
       };
       ObjectExtensions.<ManifestAccess>operator_doubleArrow(_manifest_1, _function);
     }
@@ -94,7 +95,8 @@ public class Junit4Fragment2 extends AbstractStubGeneratingFragment {
         Set<String> _exportedPackages = it.getExportedPackages();
         Grammar _grammar = this.getGrammar();
         String _eclipsePluginTestBasePackage = this._xtextGeneratorNaming.getEclipsePluginTestBasePackage(_grammar);
-        _exportedPackages.add(_eclipsePluginTestBasePackage);
+        String _plus = (_eclipsePluginTestBasePackage + ";x-internal=true");
+        _exportedPackages.add(_plus);
       };
       ObjectExtensions.<ManifestAccess>operator_doubleArrow(_manifest_3, _function_1);
     }