testDataProvider - assertion

platform/testFramework/src/com/intellij/testFramework/TestDataProvider.java

@@ -40,6 +40,11 @@ public class TestDataProvider implements DataProvider {
 
   @Override
   public Object getData(@NonNls String dataId) {
+    if (myProject.isDisposed()) {
+      throw new RuntimeException("TestDataProvider is already disposed.\n" +
+                                 "If you closed a project in test, please reset IdeaTestApplication.setDataProvider.");
+    }
+
     if (PlatformDataKeys.PROJECT.is(dataId)) {
       return myProject;
     }