Fix mockito#2915 Forbid spy on mocked interface

bmaggi · Apr 3, 2023 · a09e35f · a09e35f
1 parent f9fbf50
commit a09e35f
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diff --git a/src/main/java/org/mockito/Mockito.java b/src/main/java/org/mockito/Mockito.java
@@ -10,6 +10,7 @@
 import org.mockito.internal.creation.MockSettingsImpl;
 import org.mockito.internal.framework.DefaultMockitoFramework;
 import org.mockito.internal.session.DefaultMockitoSessionBuilder;
+import org.mockito.internal.util.MockUtil;
 import org.mockito.internal.verification.VerificationModeFactory;
 import org.mockito.invocation.Invocation;
 import org.mockito.invocation.InvocationFactory;
@@ -2167,6 +2168,10 @@ public static <T> T mock(Class<T> classToMock, MockSettings mockSettings) {
      * @return a spy of the real object
      */
     public static <T> T spy(T object) {
+        if (MockUtil.isMockOnInterface(object)) {
+            throw new IllegalArgumentException(
+                "Please don't pass interface here. Spy is not allowed on mocked interface.");
+        }
         return MOCKITO_CORE.mock(
                 (Class<T>) object.getClass(),
                 withSettings().spiedInstance(object).defaultAnswer(CALLS_REAL_METHODS));

diff --git a/src/main/java/org/mockito/internal/util/MockUtil.java b/src/main/java/org/mockito/internal/util/MockUtil.java
@@ -147,6 +147,17 @@ public static boolean isMock(Object mock) {
         return getMockHandlerOrNull(mock) != null;
     }
 
+    public static boolean isMockOnInterface(Object mock) {
+        if (mock == null) {
+            return false;
+        }
+        MockHandler<?> mockHandlerOrNull = getMockHandlerOrNull(mock);
+        if (mockHandlerOrNull == null){
+            return false;
+        }
+        return mockHandlerOrNull.getMockSettings().getTypeToMock().isInterface();
+    }
+
     private static MockHandler<?> getMockHandlerOrNull(Object mock) {
         if (mock == null) {
             throw new NotAMockException("Argument should be a mock, but is null!");

diff --git a/src/test/java/org/mockito/internal/util/MockUtilTest.java b/src/test/java/org/mockito/internal/util/MockUtilTest.java
@@ -10,6 +10,7 @@
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.withSettings;
 
+import java.util.AbstractSequentialList;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -61,6 +62,14 @@ public void should_validate_mock() {
         assertTrue(MockUtil.isMock(Mockito.mock(List.class)));
     }
 
+    @Test
+    public void should_validate_mock_on_interface() {
+        assertFalse(MockUtil.isMockOnInterface("i mock a mock"));
+        assertFalse(MockUtil.isMockOnInterface(Mockito.mock(ArrayList.class)));
+        assertFalse(MockUtil.isMockOnInterface(Mockito.mock(AbstractSequentialList.class)));
+        assertTrue(MockUtil.isMockOnInterface(Mockito.mock(List.class)));
+    }
+
     @Test
     public void should_validate_spy() {
         assertFalse(MockUtil.isSpy("i mock a mock"));

diff --git a/src/test/java/org/mockitousage/constructor/CreatingMocksWithConstructorTest.java b/src/test/java/org/mockitousage/constructor/CreatingMocksWithConstructorTest.java
@@ -409,6 +409,19 @@ public void handles_bridge_methods_correctly() {
         assertEquals("value", testBug.getValue(0));
     }
 
+
+    @Test
+    public void forbid_spy_on_mocked_interface() {
+        try {
+            spy(mock(List.class));
+            fail();
+        } catch (IllegalArgumentException e) {
+            assertThat(e)
+                .hasMessageContaining(
+                    "Please don't pass interface here. Spy is not allowed on mocked interface.");
+        }
+    }
+
     public abstract class SomeAbstractClass<T> {
 
         protected abstract String getRealValue(T value);