Issue checkstyle#5003: increase coverage of pitest-checks-whitespace …

…to 99%

pom.xml

@@ -2072,7 +2072,7 @@
               <targetTests>
                 <param>com.puppycrawl.tools.checkstyle.checks.whitespace.*</param>
               </targetTests>
-              <mutationThreshold>98</mutationThreshold>
+              <mutationThreshold>99</mutationThreshold>
               <timeoutFactor>${pitest.plugin.timeout.factor}</timeoutFactor>
               <timeoutConstant>${pitest.plugin.timeout.constant}</timeoutConstant>
               <threads>${pitest.plugin.threads}</threads>

src/main/java/com/puppycrawl/tools/checkstyle/checks/whitespace/NoWhitespaceAfterCheck.java

@@ -388,7 +388,7 @@ else if (ident.getLineNo() < ast.getLineNo()) {
         }
         //ident and lastTypeNode lay on one line
         else {
-            if (ident.getColumnNo() > ast.getColumnNo()
+            if (ident.getColumnNo() >= ast.getColumnNo() + 1
                 || lastTypeNode.getColumnNo() > ident.getColumnNo()) {
                 previousElement = lastTypeNode;
             }

src/main/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorCheck.java

@@ -140,12 +140,17 @@ private void visitEachToken(DetailAST node) {
         while (sibling != null) {
             final int columnNo = sibling.getColumnNo() - 1;
 
-            if (columnNo >= 0
+            // in such expression: "j  =123", placed at the start of the string index of the second
+            // space character will be: 2 = 0(j) + 1(whitespace) + 1(whitespace). It is a minimal
+            // possible index for the second whitespace between non-whitespace characters.
+            final int minSecondWhitespaceColumnNo = 2;
+
+            if (columnNo >= minSecondWhitespaceColumnNo
                     && !isTextSeparatedCorrectlyFromPrevious(getLine(sibling.getLineNo() - 1),
                             columnNo)) {
                 log(sibling.getLineNo(), columnNo, MSG_KEY);
             }
-            if (sibling.getChildCount() > 0) {
+            if (sibling.getChildCount() >= 1) {
                 visitEachToken(sibling.getFirstChild());
             }
 
@@ -212,8 +217,7 @@ private static boolean isSpace(String line, int columnNo) {
      *         {@code columnNo}.
      */
     private static boolean isPrecededByMultipleWhitespaces(String line, int columnNo) {
-        return columnNo >= 1
-                && Character.isWhitespace(line.charAt(columnNo))
+        return Character.isWhitespace(line.charAt(columnNo))
                 && Character.isWhitespace(line.charAt(columnNo - 1));
     }
 
@@ -239,7 +243,7 @@ private static boolean isWhitespace(String line, int columnNo) {
      *         text on the {@code line}.
      */
     private static boolean isFirstInLine(String line, int columnNo) {
-        return CommonUtils.isBlank(line.substring(0, columnNo + 1));
+        return CommonUtils.isBlank(line.substring(0, columnNo));
     }
 
     /**

src/test/java/com/puppycrawl/tools/checkstyle/checks/whitespace/SingleSpaceSeparatorCheckTest.java

@@ -20,6 +20,7 @@
 package com.puppycrawl.tools.checkstyle.checks.whitespace;
 
 import static com.puppycrawl.tools.checkstyle.checks.whitespace.SingleSpaceSeparatorCheck.MSG_KEY;
+import static org.junit.Assert.assertArrayEquals;
 
 import org.junit.Test;
 
@@ -41,6 +42,14 @@ public void testNoSpaceErrors() throws Exception {
                 CommonUtils.EMPTY_STRING_ARRAY);
     }
 
+    @Test
+    public void testGetAcceptableTokens() {
+        final SingleSpaceSeparatorCheck check = new SingleSpaceSeparatorCheck();
+
+        assertArrayEquals("Invalid acceptable tockens",
+            CommonUtils.EMPTY_INT_ARRAY, check.getAcceptableTokens());
+    }
+
     @Test
     public void testSpaceErrors() throws Exception {
         final DefaultConfiguration checkConfig =
@@ -101,6 +110,40 @@ public void testSpaceErrorsAroundComments() throws Exception {
         verify(checkConfig, getPath("InputSingleSpaceSeparatorComments.java"), expected);
     }
 
+    @Test
+    public void testSpaceErrorsInChildNodes() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(SingleSpaceSeparatorCheck.class);
+        final String[] expected = {
+            "5:15: " + getCheckMessage(MSG_KEY),
+        };
+
+        verify(checkConfig, getPath("InputSingleSpaceSeparatorChildNodes.java"), expected);
+    }
+
+    @Test
+    public void testMinColumnNo() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(SingleSpaceSeparatorCheck.class);
+        checkConfig.addAttribute("validateComments", String.valueOf(true));
+        final String[] expected = {
+            "5:3: " + getCheckMessage(MSG_KEY),
+        };
+
+        verify(checkConfig, getPath("InputSingleSpaceSeparatorMinColumnNo.java"), expected);
+    }
+
+    @Test
+    public void testWhitespaceInStartOfTheLine() throws Exception {
+        final DefaultConfiguration checkConfig =
+            createModuleConfig(SingleSpaceSeparatorCheck.class);
+        final String[] expected = {
+            "5:6: " + getCheckMessage(MSG_KEY),
+        };
+
+        verify(checkConfig, getPath("InputSingleSpaceSeparatorStartOfTheLine.java"), expected);
+    }
+
     @Test
     public void testSpaceErrorsIfCommentsIgnored() throws Exception {
         final DefaultConfiguration checkConfig =

src/test/resources/com/puppycrawl/tools/checkstyle/checks/whitespace/singlespaceseparator/InputSingleSpaceSeparatorChildNodes.java

@@ -0,0 +1,6 @@
+package com.puppycrawl.tools.checkstyle.checks.whitespace.singlespaceseparator;
+
+public class InputSingleSpaceSeparatorChildNodes {
+    int j = 0;
+    int i = 1  + j;
+}

src/test/resources/com/puppycrawl/tools/checkstyle/checks/whitespace/singlespaceseparator/InputSingleSpaceSeparatorMinColumnNo.java

@@ -0,0 +1,6 @@
+package com.puppycrawl.tools.checkstyle.checks.whitespace.singlespaceseparator;
+
+public class InputSingleSpaceSeparatorMinColumnNo {
+    int
+j  = 0;
+}

src/test/resources/com/puppycrawl/tools/checkstyle/checks/whitespace/singlespaceseparator/InputSingleSpaceSeparatorStartOfTheLine.java

@@ -0,0 +1,6 @@
+package com.puppycrawl.tools.checkstyle.checks.whitespace.singlespaceseparator;
+
+public class InputSingleSpaceSeparatorStartOfTheLine {
+    int
+   i  = 0;
+}