Mockito 3 Mocking Mockito Lenient

Strictness#STRICT_STUBS is one of the most benificial features provided by Mockito. Strictness#LENIENT was the default behaviour of Mockito 1.x but from Mockito 3.x. onwards Strictness#STRICT_STUBS will be the default behaviour.

Strictness#STRICT_STUBS make sure clean code, unnecessary and unused mock and stubbing are avoided, reduces code duplication, improves debuggability hence overall increases the performance and productivity, but some times we are not sure at invocation time which parameter will be used hence need to stub with multiple inputs. Strictness#STRICT_STUBS will not allow this and throw UnnecessaryStubbingException.

Mockito provides a way to add lenient stubs with Strictness#STRICT_STUBS.

lenient().when().thenReturn()

Mockito allows those unused stubbed which are maked with lenient

package com.example.mokito3.sujan;

public class AppleService {
    public String saveApple(String apple) {
        String appleString = "i love " + apple + " apple";
        return appleString;
    }
}

package com.example.mokito3.sujan;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoSettings;
import org.mockito.quality.Strictness;

import static org.mockito.Mockito.lenient;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

@MockitoSettings(strictness = Strictness.STRICT_STUBS)
public class AppleServiceTest {
    @Mock
    private AppleService appleService;

    @Test
    void saveAppleWithStaticMockTest() {
        AppleService appleService = mock(AppleService.class);
        lenient().when(appleService.saveApple("Fuji")).thenReturn("i eat Fuji apple");
        when(appleService.saveApple("Macintosh")).thenReturn("i eat Macintosh apple");
        String apple = appleService.saveApple("Macintosh");
        Assertions.assertEquals("i eat Macintosh apple", apple);
        verify(appleService).saveApple("Macintosh");
    }

    @Test
    void saveAppleWithAnnotationMockTest() {
        lenient().when(appleService.saveApple("Fuji")).thenReturn("i eat Fuji apple");
        when(appleService.saveApple("Macintosh")).thenReturn("i eat Macintosh apple");
        String apple = appleService.saveApple("Macintosh");
        Assertions.assertEquals("i eat Macintosh apple", apple);
        verify(appleService).saveApple("Macintosh");
    }
}

plugins {
    id 'java'
}

group 'org.example'
version '1.0-SNAPSHOT'

repositories { jcenter() }
dependencies {
    testImplementation('org.junit.jupiter:junit-jupiter:5.6.2')
    testCompile 'org.mockito:mockito-junit-jupiter:3.4.4'
}
test {
    useJUnitPlatform()
}

MockSettings#lenient

if we need all the stubs of a mock instance to be lenient then marking it with lenient is redundant, For these types of scenarios Mockito Provides MockSettings interface.

all the mocks created by

@Mock(lenient = true)
or
AppleService appleService = mock(AppleService.class, withSettings().lenient());

will be considered as lenient.

package com.example.mokito3.sujan;

public class AppleService {
    public String saveApple(String apple) {
        String appleString = "i love " + apple + " apple";
        return appleString;
    }
}

package com.example.mokito3.sujan;

import org.junit.jupiter.api.Assertions;
import org.junit.jupiter.api.Test;
import org.mockito.Mock;
import org.mockito.junit.jupiter.MockitoSettings;
import org.mockito.quality.Strictness;

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;
import static org.mockito.Mockito.withSettings;

@MockitoSettings(strictness = Strictness.STRICT_STUBS)
public class AppleServiceTest {
    @Mock(lenient = true)
    private AppleService appleService;

    @Test
    void saveAppleWithStaticMockTest() {
        AppleService appleService = mock(AppleService.class, withSettings().lenient());
        when(appleService.saveApple("Fuji")).thenReturn("i eat Fuji apple");
        when(appleService.saveApple("Macintosh")).thenReturn("i eat Macintosh apple");
        String apple = appleService.saveApple("Macintosh");
        Assertions.assertEquals("i eat Macintosh apple", apple);
        verify(appleService).saveApple("Macintosh");
    }

    @Test
    void saveAppleWithAnnotationMockTest() {
        when(appleService.saveApple("Fuji")).thenReturn("i eat Fuji apple");
        when(appleService.saveApple("Macintosh")).thenReturn("i eat Macintosh apple");
        String apple = appleService.saveApple("Macintosh");
        Assertions.assertEquals("i eat Macintosh apple", apple);
        verify(appleService).saveApple("Macintosh");
    }
}

plugins {
    id 'java'
}

group 'org.example'
version '1.0-SNAPSHOT'

repositories { jcenter() }
dependencies {
    testImplementation('org.junit.jupiter:junit-jupiter:5.6.2')
    testCompile 'org.mockito:mockito-junit-jupiter:3.4.4'
}
test {
    useJUnitPlatform()
}

Mockito 3 Mocking Mockito Lenient

MockSettings#lenient

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