BAEL-5778 @RunWith(SpringRunner.class) vs @RunWith(MockitoJUnitRunner.class) (#12991)

testing-modules/spring-mockito/pom.xml

@@ -26,6 +26,9 @@
             <artifactId>mockito-core</artifactId>
             <version>${mockito.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+        </dependency>
     </dependencies>
-
 </project>

testing-modules/spring-mockito/src/main/java/com/baeldung/runners/DataProvider.java

@@ -0,0 +1,17 @@
+package com.baeldung.runners;
+
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@Component
+public class DataProvider {
+
+    private final List<String> memory = Stream.of("baeldung", "java", "dummy").collect(Collectors.toList());
+
+    public Stream<String> getValues() {
+        return memory.stream();
+    }
+}

testing-modules/spring-mockito/src/main/java/com/baeldung/runners/StringConverter.java

@@ -0,0 +1,22 @@
+package com.baeldung.runners;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+import java.util.stream.Collectors;
+
+@Service
+public class StringConverter {
+
+    private final DataProvider dataProvider;
+
+    @Autowired
+    public StringConverter(DataProvider dataProvider) {
+        this.dataProvider = dataProvider;
+    }
+
+    public List<String> convert() {
+        return dataProvider.getValues().map(String::toUpperCase).collect(Collectors.toList());
+    }
+}

testing-modules/spring-mockito/src/main/java/com/baeldung/runners/StringConverterStarter.java

@@ -0,0 +1,11 @@
+package com.baeldung.runners;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class StringConverterStarter {
+    public static void main(String[] args) {
+        SpringApplication.run(StringConverterStarter.class, args);
+    }
+}

testing-modules/spring-mockito/src/main/resources/application.properties

@@ -1 +1,2 @@
-spring.main.allow-bean-definition-overriding=true
+spring.main.allow-bean-definition-overriding=true
+spring.main.web-application-type=none

testing-modules/spring-mockito/src/test/java/com/baeldung/runners/StringConverterMockitoRunnerUnitTest.java

@@ -0,0 +1,30 @@
+package com.baeldung.runners;
+
+import lombok.val;
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.util.stream.Stream;
+
+@RunWith(MockitoJUnitRunner.class)
+public class StringConverterMockitoRunnerUnitTest {
+    @Mock
+    private DataProvider dataProvider;
+
+    @InjectMocks
+    private StringConverter stringConverter;
+
+    @Test
+    public void givenStrings_whenConvert_thenReturnUpperCase() {
+        Mockito.when(dataProvider.getValues()).thenReturn(Stream.of("first", "second"));
+
+        val result = stringConverter.convert();
+
+        Assertions.assertThat(result).contains("FIRST", "SECOND");
+    }
+}

testing-modules/spring-mockito/src/test/java/com/baeldung/runners/StringConverterSpringRunnerUnitTest.java

@@ -0,0 +1,32 @@
+package com.baeldung.runners;
+
+import lombok.val;
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.util.stream.Stream;
+
+@ContextConfiguration(classes = StringConverter.class)
+@RunWith(SpringRunner.class)
+public class StringConverterSpringRunnerUnitTest {
+    @MockBean
+    private DataProvider dataProvider;
+
+    @Autowired
+    private StringConverter stringConverter;
+
+    @Test
+    public void givenStrings_whenConvert_thenReturnUpperCase() {
+        Mockito.when(dataProvider.getValues()).thenReturn(Stream.of("first", "second"));
+
+        val result = stringConverter.convert();
+
+        Assertions.assertThat(result).contains("FIRST", "SECOND");
+    }
+}

testing-modules/spring-mockito/src/test/java/com/baeldung/runners/StringConverterWithInitUnitTest.java

@@ -0,0 +1,37 @@
+package com.baeldung.runners;
+
+import lombok.val;
+import org.assertj.core.api.Assertions;
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.Mockito;
+import org.mockito.MockitoAnnotations;
+
+import java.util.stream.Stream;
+
+public class StringConverterWithInitUnitTest {
+    @Mock
+    private DataProvider dataProvider;
+
+    @InjectMocks
+    private StringConverter stringConverter;
+
+    @Before
+    public void init() {
+        MockitoAnnotations.openMocks(this);
+        // or
+        // dataProvider = Mockito.mock(DataProvider.class);
+        // stringConverter = new StringConverter(dataProvider);
+    }
+
+    @Test
+    public void givenStrings_whenConvert_thenReturnUpperCase() {
+        Mockito.when(dataProvider.getValues()).thenReturn(Stream.of("first", "second"));
+
+        val result = stringConverter.convert();
+
+        Assertions.assertThat(result).contains("FIRST", "SECOND");
+    }
+}