Add checkstyle rule to make sure test class names end in "Tests"

Closes gh-222

Author: philwebb

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/main/java/io/spring/javaformat/checkstyle/check/SpringTestFileNameCheck.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2017-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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 io.spring.javaformat.checkstyle.check;
+
+import java.io.File;
+
+import com.puppycrawl.tools.checkstyle.api.AbstractFileSetCheck;
+import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
+import com.puppycrawl.tools.checkstyle.api.FileText;
+
+/**
+ * Checks that test filenames end {@literal Tests.java} and not {@literal Test.java}.
+ *
+ * @author Phillip Webb
+ */
+public class SpringTestFileNameCheck extends AbstractFileSetCheck {
+
+	@Override
+	protected void processFiltered(File file, FileText fileText) throws CheckstyleException {
+		String path = file.getPath().replace('\\', '/');
+		if (path.contains("src/test/java") && file.getName().endsWith("Test.java")) {
+			log(1, "testfilename.wrongName");
+		}
+	}
+
+}

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/main/resources/io/spring/javaformat/checkstyle/check/messages.properties

@@ -26,6 +26,7 @@ methodvisibility.publicMethod=Method ''{0}'' in private class should not be publ
 nothis.unexpected=Reference to instance variable ''{0}'' should not use \"this.\".
 ternary.equalOperator=Ternary operation should use != when testing.
 ternary.missingParen=Ternary operation missing parentheses. Use the form \"(a != b) ? y : n\"
+testfilename.wrongName=Test classes should have a name ending with 'Tests.java'.
 leadingwhitespace.incorrect=Indentation should be performed with {0} only.
 deprecated.missingSince=@Deprecated has no since attribute.
 deprecated.emptySince=@Deprecated has an empty since attribute.

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/main/resources/io/spring/javaformat/checkstyle/spring-checkstyle.xml

@@ -11,6 +11,7 @@
 		<property name="headerFile" value="${headerFile}" default="" />
 		<property name="headerCopyrightPattern" value="${headerCopyrightPattern}" />
 	</module>
+	<module name="io.spring.javaformat.checkstyle.check.SpringTestFileNameCheck" />
 	<module name="com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck" />
 	<module name="com.puppycrawl.tools.checkstyle.checks.javadoc.JavadocPackageCheck" />
 

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/java/io/spring/javaformat/checkstyle/SpringChecksTests.java

@@ -21,6 +21,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -41,6 +42,7 @@
 import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
 import com.puppycrawl.tools.checkstyle.api.Configuration;
 import com.puppycrawl.tools.checkstyle.api.RootModule;
+import org.junit.jupiter.api.io.TempDir;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.MethodSource;
 import org.xml.sax.InputSource;
@@ -62,6 +64,9 @@ public class SpringChecksTests {
 
 	private static final File DEFAULT_CONFIG = new File(CONFIGS_DIR, "default-checkstyle-configuration.xml");
 
+	@TempDir
+	public Path temp;
+
 	@ParameterizedTest
 	@MethodSource("paramaters")
 	public void processHasExpectedResults(Parameter parameter) throws Exception {
@@ -118,6 +123,8 @@ public static Collection<Parameter> paramaters() throws IOException {
 			.map(Parameter::new)
 			.collect(Collectors.toCollection(ArrayList::new));
 		parameters.add(new Parameter(new File(SOURCES_DIR, "nopackageinfo/NoPackageInfo.java")));
+		parameters.add(new Parameter(new File(SOURCES_DIR, "src/test/java/NamedTest.java")));
+		parameters.add(new Parameter(new File(SOURCES_DIR, "src/test/java/NamedTests.java")));
 		return parameters;
 	}
 

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/java/io/spring/javaformat/checkstyle/SpringConfigurationLoaderTests.java

@@ -45,8 +45,8 @@ public class SpringConfigurationLoaderTests {
 	@Test
 	public void loadShouldLoadChecks() {
 		Collection<FileSetCheck> checks = load(null);
-		assertThat(checks).hasSize(4);
-		TreeWalker treeWalker = (TreeWalker) checks.toArray()[3];
+		assertThat(checks).hasSize(5);
+		TreeWalker treeWalker = (TreeWalker) checks.toArray()[4];
 		Set<?> ordinaryChecks = (Set<?>) Extractors.byName("ordinaryChecks").extract(treeWalker);
 		assertThat(ordinaryChecks).hasSize(60);
 	}
@@ -56,8 +56,8 @@ public void loadWithExcludeShouldExcludeChecks() {
 		Set<String> excludes = Collections
 			.singleton("com.puppycrawl.tools.checkstyle.checks.whitespace.MethodParamPadCheck");
 		Collection<FileSetCheck> checks = load(excludes);
-		assertThat(checks).hasSize(4);
-		TreeWalker treeWalker = (TreeWalker) checks.toArray()[3];
+		assertThat(checks).hasSize(5);
+		TreeWalker treeWalker = (TreeWalker) checks.toArray()[4];
 		Set<?> ordinaryChecks = (Set<?>) Extractors.byName("ordinaryChecks").extract(treeWalker);
 		assertThat(ordinaryChecks).hasSize(59);
 	}
@@ -66,7 +66,7 @@ public void loadWithExcludeShouldExcludeChecks() {
 	public void loadWithExcludeHeaderShouldExcludeChecks() {
 		Set<String> excludes = Collections.singleton("io.spring.javaformat.checkstyle.check.SpringHeaderCheck");
 		Object[] checks = load(excludes).stream().toArray();
-		assertThat(checks).hasSize(3);
+		assertThat(checks).hasSize(4);
 	}
 
 	private Collection<FileSetCheck> load(Set<String> excludes) {

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/resources/check/src/test/java/NamedTest.txt

@@ -0,0 +1 @@
++Test classes should have a name ending with Tests.java

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/resources/check/src/test/java/NamedTests.txt

@@ -0,0 +1 @@
++0 errors

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/resources/source/src/test/java/NamedTest.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2017-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+
+/**
+ * This is a test with the wrong name.
+ *
+ * @author Phillip Webb
+ */
+public class NamedTest {
+
+}

Diff for: spring-javaformat/spring-javaformat-checkstyle/src/test/resources/source/src/test/java/NamedTests.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2017-2023 the original author or authors.
+ *
+ * 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
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * 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.
+ */
+
+/**
+ * This is a test with the correct name.
+ *
+ * @author Phillip Webb
+ */
+public class NamedTests {
+
+}