Namespace can be created with several parts.

junit-tests/src/test/java/org/junit/gen5/engine/junit5/descriptor/ExtensionValuesStoreTest.java

@@ -159,6 +159,40 @@ void valueFromParentCanBeOverriddenInChild() {
 		}
 	}
 
+	@Nested
+	class CompositNamespaceTests {
+
+		@Test
+		void additionNamespacePartMakesADifferenc() {
+
+			Namespace ns1 = Namespace.of("part1", "part2");
+			Namespace ns2 = Namespace.of("part1");
+			Namespace ns3 = Namespace.of("part1", "part2");
+
+			Object value2 = createObject("value2");
+
+			parentStore.put(key, value, ns1);
+			parentStore.put(key, value2, ns2);
+
+			assertEquals(value, store.get(key, ns1));
+			assertEquals(value, store.get(key, ns3));
+			assertEquals(value2, store.get(key, ns2));
+		}
+
+		@Test
+		void orderOfNamespacePartsDoesNotMatter() {
+
+			Namespace ns1 = Namespace.of("part1", "part2");
+			Namespace ns2 = Namespace.of("part2", "part1");
+
+			parentStore.put(key, value, ns1);
+
+			assertEquals(value, store.get(key, ns1));
+			assertEquals(value, store.get(key, ns2));
+		}
+
+	}
+
 	private Object createObject(final String display) {
 		return new Object() {
 			@Override

junit5-api/src/main/java/org/junit/gen5/api/extension/ExtensionContext.java

@@ -11,8 +11,11 @@
 package org.junit.gen5.api.extension;
 
 import java.lang.reflect.AnnotatedElement;
+import java.util.Arrays;
+import java.util.HashSet;
 import java.util.Map;
 import java.util.Optional;
+import java.util.Set;
 import java.util.function.Function;
 
 import org.junit.gen5.commons.util.Preconditions;
@@ -112,16 +115,17 @@ public static class Namespace {
 
 		public static Namespace DEFAULT = Namespace.of(new Object());
 
-		public static Namespace of(Object ref) {
-			Preconditions.notNull(ref, "A local must not be null");
+		public static Namespace of(Object... parts) {
+			Preconditions.notEmpty(Arrays.asList(parts),
+				"There must be at least one reference object to create a namespace");
 
-			return new Namespace(ref);
+			return new Namespace(parts);
 		}
 
-		private final Object local;
+		private final Set<?> parts;
 
-		private Namespace(Object local) {
-			this.local = local;
+		private Namespace(Object... parts) {
+			this.parts = new HashSet<>(Arrays.asList(parts));
 		}
 
 		@Override
@@ -131,12 +135,12 @@ public boolean equals(Object o) {
 			if (o == null || getClass() != o.getClass())
 				return false;
 			Namespace namespace = (Namespace) o;
-			return local != null ? local.equals(namespace.local) : namespace.local == null;
+			return parts.equals(namespace.parts);
 		}
 
 		@Override
 		public int hashCode() {
-			return local != null ? local.hashCode() : 0;
+			return parts.hashCode();
 		}
 	}
 

sample-extension/src/main/java/com/example/timing/TimingExtension.java

@@ -41,13 +41,17 @@ private static class TestMethodInvocationWrapper implements BeforeEachExtensionP
 
 		@Override
 		public void beforeEach(TestExtensionContext context) throws Exception {
-			ExtensionContext.Store times = context.getStore(namespace);
+			ExtensionContext.Store times = context.getStore(getNamespace(context));
 			times.put(context.getTestMethod(), System.currentTimeMillis());
 		}
 
+		private Namespace getNamespace(TestExtensionContext context) {
+			return Namespace.of(getClass(), context);
+		}
+
 		@Override
 		public void afterEach(TestExtensionContext context) throws Exception {
-			ExtensionContext.Store times = context.getStore(namespace);
+			ExtensionContext.Store times = context.getStore(getNamespace(context));
 			Method testMethod = context.getTestMethod();
 			long start = (long) times.remove(testMethod);
 			long duration = System.currentTimeMillis() - start;