Fix #5 Handle @RunWith(SpringRunner.class) in junit 4 -> 5 migration

This depends on currently unpublished changes in rewrite core libraries

Author: sambsnyd

build.gradle.kts

@@ -68,6 +68,7 @@ dependencies {
     testImplementation("org.junit.jupiter:junit-jupiter-api:latest.release")
     testImplementation("org.junit.jupiter:junit-jupiter-params:latest.release")
     testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:latest.release")
+    testRuntimeOnly("org.springframework:spring-test:latest.release")
     "afterImplementation"("org.junit.jupiter:junit-jupiter-api:latest.release")
     "afterImplementation"("org.junit.jupiter:junit-jupiter-params:latest.release")
     "afterRuntimeOnly"("org.junit.jupiter:junit-jupiter-engine:latest.release")

src/main/java/org/openrewrite/java/testing/junit5/SpringRunnerToSpringExtension.java

@@ -0,0 +1,138 @@
+/*
+ * Copyright 2020 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.testing.junit5;
+
+import org.openrewrite.Formatting;
+import org.openrewrite.java.JavaIsoRefactorVisitor;
+import org.openrewrite.java.search.SemanticallyEqual;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.JavaType;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static org.openrewrite.Formatting.EMPTY;
+import static org.openrewrite.Tree.randomId;
+
+/**
+ * JUnit4 Spring test classes are annotated with @RunWith(SpringRunner.class)
+ * Turn this into the JUnit5-compatible @ExtendsWith(SpringExtension.class)
+ */
+public class SpringRunnerToSpringExtension extends JavaIsoRefactorVisitor {
+    private static final JavaType.Class runWithType = JavaType.Class.build("org.junit.runner.RunWith");
+    private static final J.Ident runWithIdent = J.Ident.build(
+            randomId(),
+            "RunWith",
+            runWithType,
+            EMPTY);
+    private static final JavaType.Class springRunnerType = JavaType.Class.build("org.springframework.test.context.junit4.SpringRunner");
+    private static final JavaType.Class extendWithType = JavaType.Class.build("org.junit.jupiter.api.extension.ExtendWith");
+    private static final J.Ident extendWithIdent = J.Ident.build(
+            randomId(),
+            "ExtendWith",
+            extendWithType,
+            EMPTY
+    );
+    private static final JavaType.Class springExtensionType = JavaType.Class.build("org.springframework.test.context.junit.jupiter.SpringExtension");
+
+
+    // Reference @RunWith(SpringRunner.class) annotation for semantically equal to compare against
+    private static final J.Annotation runWithSpringRunnerAnnotation = new J.Annotation(
+            randomId(),
+            runWithIdent,
+            new J.Annotation.Arguments(
+                    randomId(),
+                    Collections.singletonList(
+                            new J.FieldAccess(
+                                    randomId(),
+                                    J.Ident.build(
+                                            randomId(),
+                                            "SpringRunner",
+                                            springRunnerType,
+                                            EMPTY
+                                    ),
+                                    J.Ident.build(randomId(), "class", null, EMPTY),
+                                    JavaType.Class.build("java.lang.Class"),
+                                    EMPTY
+                            )
+                    ),
+                    EMPTY
+            ),
+            EMPTY
+    );
+
+    private static final J.Annotation extendWithSpringExtensionAnnotation = new J.Annotation(
+            randomId(),
+            extendWithIdent,
+            new J.Annotation.Arguments(
+                    randomId(),
+                    Collections.singletonList(
+                            new J.FieldAccess(
+                                    randomId(),
+                                    J.Ident.build(
+                                            randomId(),
+                                            "SpringExtension",
+                                            springExtensionType,
+                                            EMPTY
+                                    ),
+                                    J.Ident.build(randomId(), "class", null, EMPTY),
+                                    JavaType.Class.build("java.lang.Class"),
+                                    EMPTY
+                            )
+                    ),
+                    EMPTY
+            ),
+            EMPTY
+    );
+
+    public SpringRunnerToSpringExtension() {
+        setCursoringOn();
+    }
+
+    @Override
+    public J.ClassDecl visitClassDecl(J.ClassDecl cd) {
+        List<J.Annotation> annotations = cd.getAnnotations().stream()
+                .map(this::springRunnerToSpringExtension)
+                .collect(Collectors.toList());
+
+        return cd.withAnnotations(annotations);
+    }
+
+    /**
+     * Converts annotations like @RunWith(SpringRunner.class) into @ExtendWith(SpringExtension.class)
+     * Leaves other annotations untouched and returns as-is.
+     *
+     * NOT a pure function. Side effects include:
+     *      Adding imports for ExtendWith and SpringExtension
+     *      Removing imports for RunWith and SpringRunner
+     */
+    private J.Annotation springRunnerToSpringExtension(J.Annotation maybeSpringRunner) {
+        if(!new SemanticallyEqual(runWithSpringRunnerAnnotation).visit(maybeSpringRunner)) {
+            return maybeSpringRunner;
+        }
+        Formatting originalFormatting = maybeSpringRunner.getFormatting();
+        J.ClassDecl parent = getCursor().firstEnclosing(J.ClassDecl.class);
+        assert parent != null;
+        J.Annotation extendWithSpringExtension = extendWithSpringExtensionAnnotation.withFormatting(originalFormatting);
+        maybeAddImport(extendWithType);
+        maybeAddImport(springExtensionType);
+        maybeRemoveImport(springRunnerType);
+        maybeRemoveImport(runWithType);
+
+        return extendWithSpringExtension;
+    }
+}

src/test/kotlin/org/openrewrite/java/testing/junit5/SpringRunnerToSpringExtensionTest.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2020 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.testing.junit5
+
+import org.junit.Test
+import org.openrewrite.RefactorVisitorTestForParser
+import org.openrewrite.java.JavaParser
+import org.openrewrite.java.tree.J
+
+class SpringRunnerToSpringExtensionTest : RefactorVisitorTestForParser<J.CompilationUnit> {
+    override val parser: JavaParser = JavaParser.fromJavaVersion()
+            .classpath("junit", "spring-test")
+            .build()
+
+    override val visitors = listOf(SpringRunnerToSpringExtension())
+
+    @Test
+    fun basicRunnerToExtension() = assertRefactored(
+            before = """
+                import org.junit.runner.RunWith;
+                import org.springframework.test.context.junit4.SpringRunner;
+
+                @RunWith(SpringRunner.class)
+                class A {}
+            """,
+            after = """
+                import org.junit.jupiter.api.extension.ExtendWith;
+                import org.springframework.test.context.junit.jupiter.SpringExtension;
+                
+                @ExtendWith(SpringExtension.class)
+                class A {}
+            """
+    )
+
+    @Test
+    fun leavesOtherRunnersAlone() = assertUnchanged(
+            before = """
+                package a;
+                
+                import org.junit.runner.RunWith;
+                
+                @RunWith(B.class)
+                class A {}
+            """,
+            dependencies = listOf(
+                    """
+                        package a;
+                        
+                        class B {}
+                    """
+            )
+    )
+}