Fix for issue 654 ... adding unit test

Author: tglaeser

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

@@ -157,6 +157,8 @@ public void paddedCellApplyCheck() throws Exception {
 		assertFile(converge.file).hasContent("");	// converge -> converges
 		assertFile(diverge.file).hasContent("CCC");	// diverge -> no change
 
+		assertFileAttributesEqual(wellbehaved.file, wellbehaved.outputFile);
+
 		// After apply, check should pass
 		wellbehaved.check();
 		cycle.check();

testlib/src/main/java/com/diffplug/spotless/ResourceHarness.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 DiffPlug
+ * Copyright 2016-2020 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,6 +22,8 @@
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.attribute.AclEntry;
+import java.nio.file.attribute.AclFileAttributeView;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -166,6 +168,13 @@ protected void assertOnResources(FormatterFunc step, String unformattedPath, Str
 		Assert.assertEquals(expected, formatted);
 	}
 
+	/** Reads file attributes from the output file and compares it to the attributes from the input file. */
+	protected void assertFileAttributesEqual(File input, File output) throws IOException {
+		List<AclEntry> inputAttributes = Files.getFileAttributeView(input.toPath(), AclFileAttributeView.class).getAcl();
+		List<AclEntry> outputAttributes = Files.getFileAttributeView(output.toPath(), AclFileAttributeView.class).getAcl();
+		Assertions.assertThat(outputAttributes).isEqualTo(inputAttributes);
+	}
+
 	@CheckReturnValue
 	protected ReadAsserter assertFile(String path) throws IOException {
 		return new ReadAsserter(newFile(path));