Handle exceptions in test discovery phase

State: work-in-progress Addresses: #750
junit-team · Apr 11, 2017 · 0fb918f · 0fb918f
1 parent 643947e
commit 0fb918f
Show file tree

Hide file tree

Showing 2 changed files with 51 additions and 5 deletions.
diff --git a/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/DefaultLauncher.java b/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/DefaultLauncher.java
@@ -11,6 +11,7 @@
 package org.junit.platform.launcher.core;
 
 import java.util.HashSet;
+import java.util.Optional;
 import java.util.Set;
 import java.util.logging.Logger;
 
@@ -111,17 +112,32 @@ private Root discoverRoot(LauncherDiscoveryRequest discoveryRequest, String phas
 			LOG.fine(() -> String.format("Discovering tests during Launcher %s phase in engine '%s'.", phase,
 				testEngine.getId()));
 
-			UniqueId uniqueEngineId = UniqueId.forEngine(testEngine.getId());
+			Optional<TestDescriptor> engineRoot = discoverRoot(testEngine, discoveryRequest);
+			engineRoot.ifPresent(rootDescriptor -> root.add(testEngine, rootDescriptor));
+		}
+		root.applyPostDiscoveryFilters(discoveryRequest);
+		root.prune();
+		return root;
+	}
+
+	private Optional<TestDescriptor> discoverRoot(TestEngine testEngine, LauncherDiscoveryRequest discoveryRequest) {
+		UniqueId uniqueEngineId = UniqueId.forEngine(testEngine.getId());
+		try {
 			TestDescriptor engineRoot = testEngine.discover(discoveryRequest, uniqueEngineId);
 			Preconditions.notNull(engineRoot,
 				() -> String.format(
 					"The discover() method for TestEngine with ID '%s' must return a non-null root TestDescriptor.",
 					testEngine.getId()));
-			root.add(testEngine, engineRoot);
+			return Optional.of(engineRoot);
+		}
+		catch (Throwable throwable) {
+			// re-throw our own exceptions
+			if (throwable instanceof JUnitException) {
+				throw throwable;
+			}
+			LOG.warning(() -> String.format("Engine '%s' failed to discover tests: %s", testEngine.getId(), throwable));
+			return Optional.empty();
 		}
-		root.applyPostDiscoveryFilters(discoveryRequest);
-		root.prune();
-		return root;
 	}
 
 	private void execute(Root root, ConfigurationParameters configurationParameters,

diff --git a/platform-tests/src/test/java/org/junit/platform/launcher/core/DefaultLauncherTests.java b/platform-tests/src/test/java/org/junit/platform/launcher/core/DefaultLauncherTests.java
@@ -127,6 +127,36 @@ public TestDescriptor discover(org.junit.platform.engine.EngineDiscoveryRequest
 			engine.getId());
 	}
 
+	@Test
+	void discoverTestPlanForEngineThatThrowsAnErrorInDiscoverPhase() {
+		TestEngine engine = new TestEngineStub() {
+
+			@Override
+			public TestDescriptor discover(org.junit.platform.engine.EngineDiscoveryRequest discoveryRequest,
+					UniqueId uniqueId) {
+				throw new Error("ignored");
+			}
+		};
+
+		TestPlan testPlan = createLauncher(engine).discover(request().build());
+		assertThat(testPlan.getRoots()).hasSize(0);
+	}
+
+	@Test
+	void discoverTestPlanForEngineThatThrowsRuntimeExceptionInDiscoverPhase() {
+		TestEngine engine = new TestEngineStub() {
+
+			@Override
+			public TestDescriptor discover(org.junit.platform.engine.EngineDiscoveryRequest discoveryRequest,
+					UniqueId uniqueId) {
+				throw new RuntimeException("ignored");
+			}
+		};
+
+		TestPlan testPlan = createLauncher(engine).discover(request().build());
+		assertThat(testPlan.getRoots()).hasSize(0);
+	}
+
 	@Test
 	void discoverTestPlanForSingleEngine() {
 		DemoHierarchicalTestEngine engine = new DemoHierarchicalTestEngine("myEngine");