code: ///////////////////////////////////////////////////////////////////////////////////////////////
  // checkstyle: Checks Java source code and other text files for adherence to a set of rules.
  // Copyright (C) 2001-2023 the original author or authors.
  //
  // This library is free software; you can redistribute it and/or
  // modify it under the terms of the GNU Lesser General Public
  // License as published by the Free Software Foundation; either
  // version 2.1 of the License, or (at your option) any later version.
  //
  // This library is distributed in the hope that it will be useful,
  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  // Lesser General Public License for more details.
  //
  // You should have received a copy of the GNU Lesser General Public
  // License along with this library; if not, write to the Free Software
  // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  ///////////////////////////////////////////////////////////////////////////////////////////////
  
  package com.puppycrawl.tools.checkstyle.checks.header;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.header.RegexpHeaderCheck.MSG_HEADER_MISMATCH;
  import static com.puppycrawl.tools.checkstyle.checks.header.RegexpHeaderCheck.MSG_HEADER_MISSING;
  
  import java.util.List;
  import java.util.Locale;
  import java.util.regex.Pattern;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
  import com.puppycrawl.tools.checkstyle.DefaultConfiguration;
  import com.puppycrawl.tools.checkstyle.api.CheckstyleException;
  import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  /**
   * Unit test for RegexpHeaderCheck.
   */
  public class RegexpHeaderCheckTest extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/header/regexpheader";
      }
  
      /**
       * Test of setHeader method, of class RegexpHeaderCheck.
       */
      @Test
      public void testSetHeaderNull() {
          // check null passes
          final RegexpHeaderCheck instance = new RegexpHeaderCheck();
          // recreate for each test because multiple invocations fail
          final String header = null;
          instance.setHeader(header);
          final List<Pattern> headerRegexps = TestUtil.getInternalState(instance, "headerRegexps");
  
          assertWithMessage("When header is null regexps should not be set")
                  .that(headerRegexps)
                  .isEmpty();
      }
  
      /**
       * Test of setHeader method, of class RegexpHeaderCheck.
       */
      @Test
      public void testSetHeaderEmpty() {
          // check null passes
          final RegexpHeaderCheck instance = new RegexpHeaderCheck();
          // check empty string passes
          final String header = "";
          instance.setHeader(header);
          final List<Pattern> headerRegexps = TestUtil.getInternalState(instance, "headerRegexps");
  
          assertWithMessage("When header is empty regexps should not be set")
                  .that(headerRegexps)
                  .isEmpty();
      }
  
      /**
       * Test of setHeader method, of class RegexpHeaderCheck.
       */
      @Test
      public void testSetHeaderSimple() {
          final RegexpHeaderCheck instance = new RegexpHeaderCheck();
          // check valid header passes
          final String header = "abc.*";
          instance.setHeader(header);
          final List<Pattern> headerRegexps = TestUtil.getInternalState(instance, "headerRegexps");
          assertWithMessage("Expected one pattern")
              .that(headerRegexps.size())
              .isEqualTo(1);
          assertWithMessage("Invalid header regexp")
              .that(headerRegexps.get(0).pattern())
              .isEqualTo(header);
      }
  
      /**
       * Test of setHeader method, of class RegexpHeaderCheck.
       */
      @Test
      public void testSetHeader() {
          // check invalid header passes
          final RegexpHeaderCheck instance = new RegexpHeaderCheck();
          try {
              final String header = "^/**\\n * Licensed to the Apache Software Foundation (ASF)";
              instance.setHeader(header);
              assertWithMessage(String.format(Locale.ROOT, "%s should have been thrown",
                      IllegalArgumentException.class)).fail();
          }
          catch (IllegalArgumentException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("Unable to parse format: ^/**\\n *"
                      + " Licensed to the Apache Software Foundation (ASF)");
          }
      }
  
      @Test
      public void testDefaultConfiguration() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          createChecker(checkConfig);
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderDefaultConfig.java"), expected);
      }
  
      @Test
      public void testEmptyFilename() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", "");
          try {
              createChecker(checkConfig);
              assertWithMessage("Checker creation should not succeed with invalid headerFile").fail();
          }
          catch (CheckstyleException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("cannot initialize module"
                      + " com.puppycrawl.tools.checkstyle.checks.header.RegexpHeaderCheck"
                      + " - Cannot set property 'headerFile' to ''");
          }
      }
  
      @Test
      public void testRegexpHeader() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader.header"));
          final String[] expected = {
              "3: " + getCheckMessage(MSG_HEADER_MISMATCH, "// Created: 2002"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderIgnore.java"), expected);
      }
  
      @Test
      public void testNonMatchingRegexpHeader() throws Exception {
          final DefaultConfiguration checkConfig =
              createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("header",
                                  "\\/\\/ Nth Line of Header\\n\\/\\/ Nth Line of Header\\n");
          checkConfig.addProperty("multiLines", "1");
          final String[] expected = {
              "1: " + getCheckMessage(MSG_HEADER_MISMATCH, "\\/\\/ Nth Line of Header"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderNonMatching.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderUrl() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getUriString("InputRegexpHeader.header"));
          final String[] expected = {
              "3: " + getCheckMessage(MSG_HEADER_MISMATCH, "// Created: 2002"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderIgnore.java"), expected);
      }
  
      @Test
      public void testInlineRegexpHeader() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("header", "^/*$\\n// .*\\n// Created: 2002\\n^//.*\\n^//.*");
          final String[] expected = {
              "3: " + getCheckMessage(MSG_HEADER_MISMATCH, "// Created: 2002"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderIgnore.java"), expected);
      }
  
      @Test
      public void testFailureForMultilineRegexp() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("header", "^(.*\\n.*)");
          try {
              createChecker(checkConfig);
              assertWithMessage(
                      "Checker creation should not succeed when regexp spans multiple lines").fail();
          }
          catch (CheckstyleException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("cannot initialize module"
                      + " com.puppycrawl.tools.checkstyle.checks.header.RegexpHeaderCheck"
                      + " - Cannot set property 'header' to '^(.*\\n.*)'");
          }
      }
  
      @Test
      public void testInlineRegexpHeaderConsecutiveNewlines() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("header", "^/*$\\n// .*\\n\\n// Created: 2017\\n^//.*");
          final String[] expected = {
              "3: " + getCheckMessage(MSG_HEADER_MISMATCH, "^$"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderConsecutiveNewLines.java"), expected);
      }
  
      @Test
      public void testInlineRegexpHeaderConsecutiveNewlinesThroughConfigFile() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getUriString("InputRegexpHeaderNewLines.header"));
          final String[] expected = {
              "3: " + getCheckMessage(MSG_HEADER_MISMATCH, "^$"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderConsecutiveNewLines.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderIgnore() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader1.header"));
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderIgnore.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti1() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3, 6");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderDefaultConfig.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti2() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3, 6");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderMulti2.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti3() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3, 7");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderDefaultConfig.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti4() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3, 5, 6, 7");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderMulti4.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti5() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3");
          final String[] expected = {
              "1: " + getCheckMessage(MSG_HEADER_MISSING),
          };
          verify(checkConfig, getPath("InputRegexpHeaderMulti5.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti6() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2_4.header"));
          checkConfig.addProperty("multiLines", "8974382");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderMulti6.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderSmallHeader() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "3, 6");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderSmallHeader.java"), expected);
      }
  
      @Test
      public void testEmptyMultiline()
              throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader2.header"));
          checkConfig.addProperty("multiLines", "");
          final String[] expected = {
              "1: " + getCheckMessage(MSG_HEADER_MISSING),
          };
          verify(checkConfig, getPath("InputRegexpHeaderSmallHeader.java"), expected);
      }
  
      @Test
      public void testRegexpHeaderMulti52()
              throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader3.header"));
          final String[] expected = {
              "1: " + getCheckMessage(MSG_HEADER_MISSING),
          };
          verify(checkConfig, getPath("InputRegexpHeaderMulti52.java"), expected);
      }
  
      @Test
      public void testIgnoreLinesSorted() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader5.header"));
          checkConfig.addProperty("multiLines", "7,5,3");
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderIgnoreLinesSorted.java"), expected);
      }
  
      @Test
      public void testHeaderWithInvalidRegexp() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader.invalid.header"));
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          final String path = getPath("InputRegexpHeaderMulti52.java");
          try {
              verify(checkConfig, path, expected);
              assertWithMessage("IllegalArgumentException is expected").fail();
          }
          catch (IllegalArgumentException ex) {
              assertWithMessage("Invalid exception message")
                  .that(ex.getMessage())
                  .isEqualTo("line 3 in header specification is not a regular expression");
          }
      }
  
      @Test
      public void testNoWarningIfSingleLinedLeft() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader4.header"));
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(checkConfig, getPath("InputRegexpHeaderMulti5.java"), expected);
      }
  
      @Test
      public void testNoHeaderMissingErrorInCaseHeaderSizeEqualToFileSize() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(RegexpHeaderCheck.class);
          checkConfig.addProperty("headerFile", getPath("InputRegexpHeader3.header"));
          checkConfig.addProperty("multiLines", "1");
          final String[] expected = {
              "5: " + getCheckMessage(MSG_HEADER_MISMATCH, "^$"),
          };
          verify(checkConfig, getPath("InputRegexpHeaderMulti52.java"), expected);
      }
  }
  