Quick attempt at idomatic AssertJ assertions through Refaster

build.gradle.kts

@@ -33,14 +33,21 @@ dependencies {
     implementation("org.openrewrite:rewrite-java")
     implementation("org.openrewrite:rewrite-gradle")
     implementation("org.openrewrite:rewrite-maven")
+    implementation("org.openrewrite:rewrite-templating:$rewriteVersion")
     implementation("org.openrewrite.recipe:rewrite-java-dependencies:$rewriteVersion")
     implementation("org.openrewrite.recipe:rewrite-static-analysis:$rewriteVersion")
     runtimeOnly("org.openrewrite:rewrite-java-17")
 
     compileOnly("org.projectlombok:lombok:latest.release")
     annotationProcessor("org.projectlombok:lombok:latest.release")
 
+    annotationProcessor("org.openrewrite:rewrite-templating:$rewriteVersion")
+    compileOnly("com.google.errorprone:error_prone_core:2.19.1") {
+        exclude("com.google.auto.service", "auto-service-annotations")
+    }
+
     implementation("org.testcontainers:testcontainers:latest.release")
+    implementation("org.assertj:assertj-core:latest.release")
 
     testImplementation("org.openrewrite:rewrite-java-17")
     testImplementation("org.openrewrite:rewrite-groovy")
@@ -61,5 +68,4 @@ dependencies {
     testRuntimeOnly("org.testcontainers:nginx:latest.release")
 
 //    testImplementation("org.hamcrest:hamcrest:latest.release")
-//    testImplementation("org.assertj:assertj-core:latest.release")
 }

src/main/java/org/openrewrite/java/testing/assertj/IdiomaticAssertions.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2024 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.assertj;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import org.openrewrite.java.template.Primitive;
+import org.openrewrite.java.template.RecipeDescriptor;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class IdiomaticAssertions {
+    @RecipeDescriptor(
+            name = "Replace redundant `String` method calls with self",
+            description = "Replace redundant `substring(..)` and `toString()` method calls with the `String` self."
+    )
+    public static class AssertThatIsEqualToZero {
+        @BeforeTemplate
+        void before(@Primitive Integer actual) {
+            assertThat(actual).isEqualTo(0);
+        }
+
+        @AfterTemplate
+        void after(@Primitive Integer actual) {
+            assertThat(actual).isZero();
+        }
+    }
+}

src/main/resources/META-INF/rewrite/assertj.yml

@@ -28,6 +28,7 @@ recipeList:
   - org.openrewrite.java.testing.assertj.IsEqualToBoolean
   - org.openrewrite.java.testing.assertj.SimplifyChainedAssertJAssertions
   - org.openrewrite.java.testing.assertj.IsEqualToEmptyString
+  - org.openrewrite.java.testing.assertj.IdiomaticAssertionsRecipes
 
 ---
 type: specs.openrewrite.org/v1beta/recipe

src/test/java/org/openrewrite/java/testing/assertj/IdiomaticAssertionsTest.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2024 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.assertj;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.InMemoryExecutionContext;
+import org.openrewrite.java.JavaParser;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+
+class IdiomaticAssertionsTest implements RewriteTest {
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec
+          .parser(JavaParser.fromJavaVersion().classpathFromResources(new InMemoryExecutionContext(), "assertj-core-3.24"))
+          .recipe(new IdiomaticAssertionsRecipes());
+    }
+
+    @Test
+    @DocumentExample
+    void intIsEqualToZero() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import static org.assertj.core.api.Assertions.assertThat;
+              class Test {
+                  void test(int i) {
+                      assertThat(i).isEqualTo(0);
+                      assertThat(i).isNotEqualTo(0);
+                  }
+              }
+              """,
+            """
+              import static org.assertj.core.api.Assertions.assertThat;
+              class Test {
+                  void test(int i) {
+                      assertThat(i).isZero();
+                      assertThat(i).isNotZero();
+                  }
+              }
+              """
+          )
+        );
+    }
+}