Duplicate class test for testing dexopt

Bug: 208978971
Change-Id: I95e7231aeafc640448bfb7cae8d7657687aea3cd
diff --git a/src/test/java/com/android/tools/r8/apimodel/DuplicateClassTest.java b/src/test/java/com/android/tools/r8/apimodel/DuplicateClassTest.java
new file mode 100644
index 0000000..458bb9d
--- /dev/null
+++ b/src/test/java/com/android/tools/r8/apimodel/DuplicateClassTest.java
@@ -0,0 +1,69 @@
+// Copyright (c) 2021, the R8 project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+package com.android.tools.r8.apimodel;
+
+import static org.hamcrest.CoreMatchers.containsString;
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import com.android.tools.r8.TestBase;
+import com.android.tools.r8.TestParameters;
+import com.android.tools.r8.TestParametersCollection;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameter;
+import org.junit.runners.Parameterized.Parameters;
+
+@RunWith(Parameterized.class)
+/**
+ * A simple test showing that adding a program class as a duplicate for a bootclasspath class for
+ * dalvik causes an error where the referencing class cannot be optimized (b/208978971).
+ */
+public class DuplicateClassTest extends TestBase {
+
+  @Parameter() public TestParameters parameters;
+
+  @Parameters(name = "{0}")
+  public static TestParametersCollection data() {
+    return getTestParameters().withDexRuntimes().withAllApiLevels().build();
+  }
+
+  @Test
+  public void testRuntime() throws Exception {
+    testForD8(parameters.getBackend())
+        .addProgramClassFileData(
+            transformer(Main.class).removeInnerClasses().transform(),
+            transformer(Foo.class)
+                .setClassDescriptor("Ljava/lang/Exception;")
+                .removeInnerClasses()
+                .transform())
+        .setMinApi(parameters.getApiLevel())
+        .compile()
+        .run(parameters.getRuntime(), Main.class)
+        .assertSuccessWithOutputLines("Hello World")
+        .applyIf(
+            parameters.getDexRuntimeVersion().isDalvik(),
+            result ->
+                assertThat(
+                    result.getStdErr(),
+                    containsString(
+                        "DexOpt: not resolving ambiguous class 'Ljava/lang/Exception;'")),
+            result ->
+                assertThat(
+                    result.getStdErr(),
+                    not(containsString("not resolving ambiguous class 'Ljava/lang/Exception;'"))));
+  }
+
+  public static class Main {
+
+    public static void main(String[] args) {
+      Exception exception = new Exception("Hello World");
+      System.out.println(exception.getMessage());
+    }
+  }
+
+  public static class /* java.lang.Exception */ Foo {}
+}