Issue checkstyle#13809: Kill mutation in Tree-Walker-2

Author: Kevin222004

config/pitest-suppressions/pitest-tree-walker-suppressions.xml

@@ -80,13 +80,4 @@
     <description>removed call to java/util/Comparator::naturalOrder</description>
     <lineContent>Comparator.nullsLast(Comparator.naturalOrder()))</lineContent>
   </mutation>
-
-  <mutation unstable="false">
-    <sourceFile>TreeWalker.java</sourceFile>
-    <mutatedClass>com.puppycrawl.tools.checkstyle.TreeWalker</mutatedClass>
-    <mutatedMethod>lambda$createNewCheckSortedSet$3</mutatedMethod>
-    <mutator>org.pitest.mutationtest.engine.gregor.mutators.returns.EmptyObjectReturnValsMutator</mutator>
-    <description>replaced return value with &quot;&quot; for com/puppycrawl/tools/checkstyle/TreeWalker::lambda$createNewCheckSortedSet$3</description>
-    <lineContent>Comparator.&lt;AbstractCheck, String&gt;comparing(check -&gt; check.getClass().getName())</lineContent>
-  </mutation>
 </suppressedMutations>

src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java

@@ -33,6 +33,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
@@ -679,6 +680,38 @@ public void testExternalResourceFiltersWithNoExternalResource() throws Exception
         verify(checkerConfig, filePath, expected);
     }
 
+    /**
+     * This test is checking that Checks execution ordered by name.
+     *
+     * @throws Exception if file is not found
+     */
+    @Test
+    public void testOrderOfCheckExecution() throws Exception {
+
+        final DefaultConfiguration configuration1 = createModuleConfig(AaCheck.class);
+        configuration1.addProperty("id", "2");
+        final DefaultConfiguration configuration2 = createModuleConfig(BbCheck.class);
+        configuration2.addProperty("id", "1");
+
+        final DefaultConfiguration treeWalkerConfig = createModuleConfig(TreeWalker.class);
+        treeWalkerConfig.addChild(configuration2);
+        treeWalkerConfig.addChild(configuration1);
+
+        final List<File> files =
+                Collections.singletonList(new File(getPath("InputTreeWalker2.java")));
+        final Checker checker = createChecker(treeWalkerConfig);
+
+        try {
+            checker.process(files);
+            assertWithMessage("exception is expected").fail();
+        }
+        catch (CheckstyleException exception) {
+            assertWithMessage("wrong order of Check executions")
+                    .that(exception.getCause().getMessage())
+                    .isEqualTo(AaCheck.class.toString());
+        }
+    }
+
     public static class BadJavaDocCheck extends AbstractCheck {
 
         @Override
@@ -773,6 +806,54 @@ public boolean isCommentNodesRequired() {
 
     }
 
+    public static class AaCheck extends AbstractCheck {
+
+        @Override
+        public int[] getDefaultTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public int[] getAcceptableTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public int[] getRequiredTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public void beginTree(DetailAST rootAST) {
+            throw new IllegalStateException(AaCheck.class.toString());
+        }
+
+    }
+
+    public static class BbCheck extends AbstractCheck {
+
+        @Override
+        public int[] getDefaultTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public int[] getAcceptableTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public int[] getRequiredTokens() {
+            return new int[0];
+        }
+
+        @Override
+        public void beginTree(DetailAST rootAST) {
+            throw new IllegalStateException(BbCheck.class.toString());
+        }
+
+    }
+
     public static class RequiredTokenIsEmptyIntArray extends AbstractCheck {
 
         @Override

src/test/resources/com/puppycrawl/tools/checkstyle/treewalker/InputTreeWalker2.java

@@ -0,0 +1,4 @@
+package com.puppycrawl.tools.checkstyle.treewalker;
+
+public class InputTreeWalker2 {
+}