1 files changed, 46 insertions, 0 deletions
diff --git a/examples/junit/src/test/java/com/example/MutatorFuzzTest.java b/examples/junit/src/test/java/com/example/MutatorFuzzTest.java
new file mode 100644
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--- /dev/null
+++ b/examples/junit/src/test/java/com/example/MutatorFuzzTest.java
@@ -0,0 +1,46 @@
+/*
+ * Copyright 2023 Code Intelligence GmbH
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import com.code_intelligence.jazzer.driver.FuzzTargetRunner;
+import com.code_intelligence.jazzer.junit.FuzzTest;
+import com.code_intelligence.jazzer.mutation.annotation.NotNull;
+import java.util.List;
+import org.junit.jupiter.api.AfterAll;
+
+class MutatorFuzzTest {
+  @FuzzTest
+  void mutatorFuzz(List<@NotNull String> list) {
+    // Check that the mutator is actually doing something.
+    if (list != null && list.size() > 3 && list.get(2).equals("mutator")) {
+      throw new AssertionError("Found expected JUnit mutator test issue");
+    }
+  }
+
+  @AfterAll
+  static void assertFuzzTargetRunner() {
+    // FuzzTargetRunner values are not set in JUnit engine tests.
+    String jazzerFuzz = System.getenv("JAZZER_FUZZ");
+    if (jazzerFuzz != null && !jazzerFuzz.isEmpty()) {
+      assertTrue(FuzzTargetRunner.invalidCorpusFilesPresent());
+      assertEquals(FuzzTargetRunner.mutatorDebugString(), "Arguments[Nullable<List<String>>]");
+    }
+  }
+}