Merge pull request #1088 from jqno/improve-mockito-error-message

Improves MockitoException error message

Author: jqno

CHANGELOG.md

@@ -18,6 +18,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Support for Kotlin delegates. ([Issue 1083](https://github.com/jqno/equalsverifier/issues/1083))
 
+### Changed
+
+- When a Mockito error occurs, the error message now says which mocked method was attempted to call. ([Issue 1082](https://github.com/jqno/equalsverifier/issues/1082))
+
 ## [4.0.1] - 2025-06-10
 
 ### Fixed

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/internal/exceptions/MockitoException.java

@@ -3,13 +3,17 @@
 import nl.jqno.equalsverifier.internal.util.Formatter;
 
 public class MockitoException extends MessagingException {
-    public MockitoException(String fieldName, String typeName) {
+    public MockitoException(String fieldName, String typeName, String methodName) {
         super(Formatter
                 .of(
                     """
-                    Unable to use Mockito to mock field %% of type %%.
-                       Please provide a prefab value for this type, or use #set(Mode.skipMockito()) to skip using Mockito altogether.""",
+                    Unable to use Mockito to mock field %%:
+                       tried to call method %%.%%, which EqualsVerifier can't mock.
+                       Please provide a prefab value for type %%,
+                       or use #set(Mode.skipMockito()) to skip using Mockito altogether.""",
                     fieldName,
+                    typeName,
+                    methodName,
                     typeName)
                 .format());
     }

equalsverifier-core/src/main/java/nl/jqno/equalsverifier/internal/instantiation/MockitoValueProvider.java

@@ -63,7 +63,7 @@ public <T> Optional<Tuple<T>> provide(TypeTag tag, String fieldName) {
     private <T> T buildMock(Class<T> type, String fieldName) {
         return mock(type, withSettings().defaultAnswer(invocation -> {
             // Throw an exception on any method except equals and hashCode
-            throw new MockitoException(fieldName, type.getSimpleName());
+            throw new MockitoException(fieldName, type.getSimpleName(), invocation.getMethod().getName());
         }));
     }
 }

equalsverifier-test-mockito/src/test/java/nl/jqno/equalsverifier/mockito/MockitoTest.java

@@ -39,7 +39,9 @@ void verifyClassThatCallsDirectlyIntoField() {
                             .verify())
                 .assertFailure()
                 .assertCause(MockitoException.class)
-                .assertMessageContains("Unable to use Mockito to mock field methodCaller of type PojoWithoutEquals.");
+                .assertMessageContains(
+                    "Unable to use Mockito to mock field methodCaller",
+                    "tried to call method PojoWithoutEquals.getI");
     }
 
     @Test
@@ -64,7 +66,9 @@ void verifyClassThatContainsSparseArrayThatCallsMethods() {
                 .when(() -> EqualsVerifier.forClass(SparseArrayEqualsContainer.class).verify())
                 .assertFailure()
                 .assertCause(MockitoException.class)
-                .assertMessageContains("Unable to use Mockito to mock field sparseArray of type SparseArray");
+                .assertMessageContains(
+                    "Unable to use Mockito to mock field sparseArray",
+                    "tried to call method SparseArray.size");
     }
 
     @Test