mutator: Add support for empty proto messages

2 files changed, 22 insertions, 0 deletions

diff --git a/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/BuilderMutatorProto3Test.java b/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/BuilderMutatorProto3Test.java
index cb54a146..7e1a727e 100644
--- a/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/BuilderMutatorProto3Test.java
+++ b/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/BuilderMutatorProto3Test.java
@@ -28,6 +28,7 @@ import com.code_intelligence.jazzer.mutation.mutator.collection.CollectionMutato
 import com.code_intelligence.jazzer.mutation.mutator.lang.LangMutators;
 import com.code_intelligence.jazzer.mutation.support.TestSupport.MockPseudoRandom;
 import com.code_intelligence.jazzer.mutation.support.TypeHolder;
+import com.code_intelligence.jazzer.protobuf.Proto3.EmptyMessage3;
 import com.code_intelligence.jazzer.protobuf.Proto3.EnumField3;
 import com.code_intelligence.jazzer.protobuf.Proto3.EnumField3.TestEnum;
 import com.code_intelligence.jazzer.protobuf.Proto3.EnumFieldOne3;
@@ -482,4 +483,23 @@ class BuilderMutatorProto3Test {
         .isEqualTo(OneOfField3.newBuilder().setOtherField(true).setYetAnotherField(true).build());
     assertThat(builder.build().hasMessageField()).isFalse();
   }
+
+  @Test
+  void testEmptyMessage3() {
+    InPlaceMutator<EmptyMessage3.Builder> mutator =
+        (InPlaceMutator<EmptyMessage3.Builder>) FACTORY.createInPlaceOrThrow(
+            new TypeHolder<EmptyMessage3.@NotNull Builder>() {}.annotatedType());
+    assertThat(mutator.toString()).isEqualTo("FixedValue()");
+    EmptyMessage3.Builder builder = EmptyMessage3.newBuilder();
+
+    try (MockPseudoRandom prng = mockPseudoRandom()) {
+      mutator.initInPlace(builder, prng);
+    }
+    assertThat(builder.build()).isEqualTo(EmptyMessage3.getDefaultInstance());
+
+    try (MockPseudoRandom prng = mockPseudoRandom()) {
+      mutator.mutateInPlace(builder, prng);
+    }
+    assertThat(builder.build()).isEqualTo(EmptyMessage3.getDefaultInstance());
+  }
 }
diff --git a/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/proto3.proto b/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/proto3.proto
index 88003345..32451a7d 100644
--- a/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/proto3.proto
+++ b/src/test/java/com/code_intelligence/jazzer/mutation/mutator/proto/proto3.proto
@@ -128,3 +128,5 @@ message DoubleField3 {
 message RepeatedDoubleField3 {
   repeated double some_field = 1;
 }
+
+message EmptyMessage3 {}