MockitoMockClassReference

SUGGESTION

Simplification

View source code on GitHub

Summary

Don’t unnecessarily pass a type to Mockito’s mock(Class) and spy(Class) methods

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("MockitoMockClassReference") to the enclosing element.

Disable this pattern completely by adding -Xep:MockitoMockClassReference:OFF as compiler argument. Learn more.

Samples

Replacement

Shows the difference in example code before and after the bug pattern is applied.

 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.withSettings;
 
 import org.mockito.invocation.InvocationOnMock;
 
 class A {
   void m() {
-    Number simpleMock = mock(Number.class);
-    Number namedMock = mock(Number.class, "name");
-    Number customAnswerMock = mock(Number.class, InvocationOnMock::callRealMethod);
-    Number customSettingsMock = mock(Number.class, withSettings());
-    Number simpleSpy = spy(Number.class);
+    Number simpleMock = mock();
+    Number namedMock = mock("name");
+    Number customAnswerMock = mock(InvocationOnMock::callRealMethod);
+    Number customSettingsMock = mock(withSettings());
+    Number simpleSpy = spy();
   }
 }
 

Identification

Shows code lines which will (not) be flagged by this bug pattern.
A //BUG: Diagnostic contains: comment is placed above any violating line.

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.withSettings;

import java.util.List;
import java.util.Objects;
import org.mockito.invocation.InvocationOnMock;

class A {
  {
    Double d = Objects.requireNonNullElseGet(null, () -> mock(Double.class));
    Double d2 =
        Objects.requireNonNullElseGet(
            null,
            () -> {
              return mock(Double.class);
            });
  }

  void m() {
    Number variableMock = 42;
    // BUG: Diagnostic contains:
    variableMock = mock(Number.class);
    // BUG: Diagnostic contains:
    variableMock = mock(Number.class, "name");
    // BUG: Diagnostic contains:
    variableMock = mock(Number.class, InvocationOnMock::callRealMethod);
    // BUG: Diagnostic contains:
    variableMock = mock(Number.class, withSettings());
    variableMock = mock(Integer.class);
    variableMock = 42;
    // BUG: Diagnostic contains:
    List rawMock = mock(List.class);
    // BUG: Diagnostic contains:
    List<String> genericMock = mock(List.class);
    var varMock = mock(Integer.class);
    Class<? extends Number> numberType = Integer.class;
    Number variableTypeMock = mock(numberType);
    Object subtypeMock = mock(Integer.class);

    Number variableSpy = 42;
    // BUG: Diagnostic contains:
    variableSpy = spy(Number.class);
    variableSpy = spy(Integer.class);
    variableSpy = 42;
    // BUG: Diagnostic contains:
    List rawSpy = spy(List.class);
    // BUG: Diagnostic contains:
    List<String> genericSpy = spy(List.class);
    var varSpy = spy(Integer.class);
    Number variableTypeSpy = spy(numberType);
    Object subtypeSpy = spy(Integer.class);
    Object objectSpy = spy(new Object());

    Objects.hash(mock(Integer.class));
    Integer i = mock(mock(Integer.class));
    String s = new String(mock(String.class));
  }

  Double getDoubleMock() {
    return Objects.requireNonNullElseGet(
        null,
        () -> {
          return mock(Double.class);
        });
  }

  Integer getIntegerMock() {
    // BUG: Diagnostic contains:
    return mock(Integer.class);
  }

  <T> T getGenericMock(Class<T> clazz) {
    return mock(clazz);
  }

  Number getSubTypeMock() {
    return mock(Integer.class);
  }
}