feat: test new api for indentation spaces vs. tabs

- check for deprecation warnings but retained functionality of old api
- check functionality of new api

Refs: #794, #2311

Author: simschla

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/IndentIntegrationTest.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2021-2024 DiffPlug
+ *
+ * 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
+ *
+ *     http://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 com.diffplug.gradle.spotless;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.io.IOException;
+import java.util.stream.Stream;
+
+import org.gradle.testkit.runner.BuildResult;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class IndentIntegrationTest extends GradleIntegrationHarness {
+
+	@ParameterizedTest
+	@ValueSource(strings = {"indentWithSpaces", "indentWithTabs"})
+	void oldIndentApiLogsDeprecationWarning(String indentationMethodName) throws IOException {
+		BuildResult result = runIndentFormatter(indentationMethodName);
+		assertThat(result.getOutput()).containsPattern(".*" + indentationMethodName + ".*deprecated.*");
+	}
+
+	@ParameterizedTest
+	@ValueSource(strings = {"leadingTabsToSpaces", "leadingSpacesToTabs"})
+	void newIndentApiDoesNotLogDeprecationWarning(String indentationMethodName) throws IOException {
+		BuildResult result = runIndentFormatter(indentationMethodName);
+		assertThat(result.getOutput()).doesNotContainPattern(".*" + indentationMethodName + ".*deprecated.*");
+	}
+
+	@ParameterizedTest(name = "{0}")
+	@MethodSource("indentationCombinations")
+	void indentationCombinations(String testName, String indentationMethodName, String actualResource, String expectedResultResource) throws IOException {
+		runIndentFormatter(indentationMethodName, actualResource);
+		assertFile("test.txt").sameAsResource(expectedResultResource);
+	}
+
+	private static Stream<Arguments> indentationCombinations() {
+		return Stream.of(
+				// new API
+				Arguments.of("tabsToTabs", "leadingSpacesToTabs", "indent/IndentedWithTab.test", "indent/IndentedWithTab.test"),
+				Arguments.of("spacesToSpaces", "leadingTabsToSpaces", "indent/IndentedWithSpace.test", "indent/IndentedWithSpace.test"),
+				Arguments.of("spacesToTabs", "leadingSpacesToTabs", "indent/IndentedWithSpace.test", "indent/IndentedWithTab.test"),
+				Arguments.of("tabsToSpaces", "leadingTabsToSpaces", "indent/IndentedWithTab.test", "indent/IndentedWithSpace.test"),
+				Arguments.of("mixedToTabs", "leadingSpacesToTabs", "indent/IndentedMixed.test", "indent/IndentedWithTab.test"),
+				Arguments.of("mixedToSpaces", "leadingTabsToSpaces", "indent/IndentedMixed.test", "indent/IndentedWithSpace.test"),
+				// legacy API
+				Arguments.of("legacy: tabsToTabs", "indentWithTabs", "indent/IndentedWithTab.test", "indent/IndentedWithTab.test"),
+				Arguments.of("legacy: spacesToSpaces", "indentWithSpaces", "indent/IndentedWithSpace.test", "indent/IndentedWithSpace.test"),
+				Arguments.of("legacy: spacesToTabs", "indentWithTabs", "indent/IndentedWithSpace.test", "indent/IndentedWithTab.test"),
+				Arguments.of("legacy: tabsToSpaces", "indentWithSpaces", "indent/IndentedWithTab.test", "indent/IndentedWithSpace.test"),
+				Arguments.of("legacy: mixedToTabs", "indentWithTabs", "indent/IndentedMixed.test", "indent/IndentedWithTab.test"),
+				Arguments.of("legacy: mixedToSpaces", "indentWithSpaces", "indent/IndentedMixed.test", "indent/IndentedWithSpace.test"));
+	}
+
+	private BuildResult runIndentFormatter(String indentationMethodName) throws IOException {
+		return runIndentFormatter(indentationMethodName, "indent/IndentedMixed.test");
+	}
+
+	private BuildResult runIndentFormatter(String indentationMethodName, String resourceFile) throws IOException {
+		setFile("build.gradle").toLines(
+				"plugins {",
+				"  id 'com.diffplug.spotless'",
+				"}",
+				"spotless {",
+				"  format 'test', {",
+				"    target '**/*.txt'",
+				"    " + indentationMethodName + "()",
+				"  }",
+				"}");
+		setFile("test.txt").toResource(resourceFile);
+		BuildResult result = gradleRunner().withArguments("spotlessApply").build();
+		return result;
+	}
+
+}

testlib/src/main/resources/indent/IndentedMixed.test

@@ -0,0 +1,37 @@
+package com.github.youribonnaffe.gradle.format;
+
+import java.util.function.Function;
+
+/**
+ * Test class.
+ */
+public class Java8Test {
+    /**
+     * Test method.
+     */
+    public void doStuff() throws Exception {
+        Function<String, Integer> example = Integer::parseInt;
+        example.andThen(val -> {
+            return val + 2;
+        } );
+        SimpleEnum val = SimpleEnum.A;
+        switch (val) {
+            case A:
+                break;
+            case B:
+                break;
+            case C:
+                break;
+            default:
+                throw new Exception();
+        }
+    }
+
+	/** Test enum
+	* with weirdly formatted javadoc
+	* which IndentStep should not change
+	*/
+	public enum SimpleEnum {
+		A, B, C;
+	}
+}