WIP Mockito strict stubs enforcement

error-prone-contrib/pom.xml

@@ -147,6 +147,11 @@
             <artifactId>mockito-core</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.reactivestreams</groupId>
             <artifactId>reactive-streams</artifactId>

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoAnnotationCheck.java

@@ -0,0 +1,75 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Description.NO_MATCH;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.hasArgumentWithValue;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.isType;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.BugPattern.LinkType;
+import com.google.errorprone.BugPattern.ProvidesFix;
+import com.google.errorprone.BugPattern.SeverityLevel;
+import com.google.errorprone.BugPattern.StandardTags;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.MultiMatcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.Tree;
+
+/** A {@link BugChecker} which flags classes importing Mockito, but not enforcing strict mocks. */
+@AutoService(BugChecker.class)
+@BugPattern(
+    name = "MockitoAnnotation",
+    summary = "Prefer using strict stubs with Mockito",
+    linkType = LinkType.NONE,
+    severity = SeverityLevel.SUGGESTION,
+    tags = StandardTags.STYLE,
+    providesFix = ProvidesFix.REQUIRES_HUMAN_ATTENTION)
+public final class MockitoAnnotationCheck extends BugChecker implements ClassTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final String MOCKITO_SETTINGS = "org.mockito.junit.jupiter.MockitoSettings";
+  private static final String STRICT_STUBS = "org.mockito.quality.Strictness.STRICT_STUBS";
+  private static final String MOCKITO_ANNOTATION = "@MockitoSettings(strictness = STRICT_STUBS)";
+  private static final MultiMatcher<Tree, AnnotationTree> HAS_STRICT_STUBS_ANNOTATION =
+      annotations(
+          AT_LEAST_ONE,
+          allOf(
+              isType(MOCKITO_SETTINGS),
+              hasArgumentWithValue("strictness", isSameType(STRICT_STUBS))));
+
+  @Override
+  public Description matchClass(ClassTree clazz, VisitorState state) {
+    if (ASTHelpers.findEnclosingNode(state.getPath(), ClassTree.class) != null
+        || HAS_STRICT_STUBS_ANNOTATION.matches(clazz, state)
+        || !importsMockito(state)) {
+      return NO_MATCH;
+    }
+
+    return describeMatch(clazz, buildFix(clazz));
+  }
+
+  private static boolean importsMockito(VisitorState state) {
+    return state.getPath().getCompilationUnit().getImports().stream()
+        .map(ImportTree::getQualifiedIdentifier)
+        .map(Object::toString)
+        .anyMatch(importLine -> importLine.startsWith("org.mockito"));
+  }
+
+  private static SuggestedFix buildFix(ClassTree clazz) {
+    return SuggestedFix.builder()
+        .addImport(MOCKITO_SETTINGS)
+        .addStaticImport(STRICT_STUBS)
+        .prefixWith(clazz, MOCKITO_ANNOTATION)
+        .build();
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/MockitoAnnotationCheckTest.java

@@ -0,0 +1,71 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+public final class MockitoAnnotationCheckTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(MockitoAnnotationCheck.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(new MockitoAnnotationCheck(), getClass());
+
+  @Test
+  public void testIdentification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static org.mockito.Mockito.mock;",
+            "",
+            "import org.junit.jupiter.api.Tag;",
+            "import org.junit.jupiter.api.Test;",
+            "",
+            "@Tag(\"unit\")",
+            "// BUG: Diagnostic contains:",
+            "class MockitoTest {",
+            "    @Test",
+            "    void mockitoTest() {",
+            "        mock(String.class);",
+            "    }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  public void testReplacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import static org.mockito.Mockito.mock;",
+            "",
+            "import org.junit.jupiter.api.Tag;",
+            "import org.junit.jupiter.api.Test;",
+            "",
+            "@Tag(\"unit\")",
+            "class MockitoTest {",
+            "    @Test",
+            "    void mockitoTest() {",
+            "        mock(String.class);",
+            "    }",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import static org.mockito.Mockito.mock;",
+            "import static org.mockito.quality.Strictness.STRICT_STUBS;",
+            "",
+            "import org.junit.jupiter.api.Tag;",
+            "import org.junit.jupiter.api.Test;",
+            "import org.mockito.junit.jupiter.MockitoSettings;",
+            "",
+            "@MockitoSettings(strictness = STRICT_STUBS)",
+            "@Tag(\"unit\")",
+            "class MockitoTest {",
+            "    @Test",
+            "    void mockitoTest() {",
+            "        mock(String.class);",
+            "    }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

pom.xml

@@ -296,6 +296,11 @@
                 <artifactId>mockito-core</artifactId>
                 <version>${version.mockito}</version>
             </dependency>
+            <dependency>
+                <groupId>org.mockito</groupId>
+                <artifactId>mockito-junit-jupiter</artifactId>
+                <version>${version.mockito}</version>
+            </dependency>
             <dependency>
                 <groupId>org.reactivestreams</groupId>
                 <artifactId>reactive-streams</artifactId>