Ensure correct test class is supplied to outer class extensions

This commit refactors TestInstancePostProcessorTests to ensure that the
appropriate test class is provided via the ExtensionContext when an
extension is applied at the outer test class level while executing a
@nested test class.

Issue: #912

Author: sbrannen

junit-jupiter-engine/src/test/java/org/junit/jupiter/engine/extension/TestInstancePostProcessorTests.java

@@ -104,7 +104,7 @@ void beforeOuterMethod() {
 
 		@Test
 		void testOuter() {
-			assertEquals("foo", outerName);
+			assertEquals("foo:" + OuterTestCase.class.getSimpleName(), outerName);
 			callSequence.add("testOuter");
 		}
 
@@ -126,8 +126,8 @@ void beforeInnerMethod() {
 
 			@Test
 			void testInner() {
-				assertEquals("foo", outerName);
-				assertEquals("bar", innerName);
+				assertEquals("foo:" + OuterTestCase.class.getSimpleName(), outerName);
+				assertEquals("bar:" + InnerTestCase.class.getSimpleName(), innerName);
 				callSequence.add("testInner");
 			}
 		}
@@ -152,7 +152,7 @@ void beforeEachMethod() {
 		@Test
 		void test() {
 			callSequence.add("test");
-			assertEquals("foo", name);
+			assertEquals("foo:" + getClass().getSimpleName(), name);
 		}
 	}
 
@@ -161,7 +161,7 @@ private static class FooInstancePostProcessor implements TestInstancePostProcess
 		@Override
 		public void postProcessTestInstance(Object testInstance, ExtensionContext context) throws Exception {
 			if (testInstance instanceof Named) {
-				((Named) testInstance).setName("foo");
+				((Named) testInstance).setName("foo:" + context.getTestClass().get().getSimpleName());
 			}
 			callSequence.add("fooPostProcessTestInstance:" + testInstance.getClass().getSimpleName());
 		}
@@ -172,7 +172,7 @@ private static class BarInstancePostProcessor implements TestInstancePostProcess
 		@Override
 		public void postProcessTestInstance(Object testInstance, ExtensionContext context) throws Exception {
 			if (testInstance instanceof Named) {
-				((Named) testInstance).setName("bar");
+				((Named) testInstance).setName("bar:" + context.getTestClass().get().getSimpleName());
 			}
 			callSequence.add("barPostProcessTestInstance:" + testInstance.getClass().getSimpleName());
 		}