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.regexp;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.regexp.SinglelineDetector.MSG_REGEXP_EXCEEDED;
  import static com.puppycrawl.tools.checkstyle.checks.regexp.SinglelineDetector.MSG_REGEXP_MINIMUM;
  
  import java.io.File;
  import java.nio.charset.StandardCharsets;
  
  import org.junit.jupiter.api.Test;
  
  import com.puppycrawl.tools.checkstyle.AbstractModuleTestSupport;
  import com.puppycrawl.tools.checkstyle.api.FileText;
  import com.puppycrawl.tools.checkstyle.internal.testmodules.TestLoggingReporter;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  public class RegexpSinglelineCheckTest extends AbstractModuleTestSupport {
  
      private static final String[] EMPTY = {};
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/regexp/regexpsingleline";
      }
  
      @Test
      public void testIt() throws Exception {
          final String[] expected = {
              "77: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "System\\.(out)|(err)\\.print(ln)?\\("),
          };
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic.java"), expected);
      }
  
      @Test
      public void testMessageProperty()
              throws Exception {
          final String[] expected = {
              "78: Bad line :(",
          };
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic2.java"), expected);
      }
  
      @Test
      public void testIgnoreCaseTrue() throws Exception {
  
          final String[] expected = {
              "78: " + getCheckMessage(MSG_REGEXP_EXCEEDED, "SYSTEM\\.(OUT)|(ERR)\\.PRINT(LN)?\\("),
          };
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic3.java"), expected);
      }
  
      @Test
      public void testIgnoreCaseFalse() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic4.java"), expected);
      }
  
      @Test
      public void testMinimum() throws Exception {
          final String[] expected = {
              "1: " + getCheckMessage(MSG_REGEXP_MINIMUM, "500", "\\r"),
          };
  
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic5.java"), expected);
      }
  
      @Test
      public void testSetMessage() throws Exception {
          final String[] expected = {
              "1: someMessage",
          };
  
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic6.java"), expected);
      }
  
      @Test
      public void testMaximum() throws Exception {
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic7.java"), EMPTY);
      }
  
      /**
       * Done as a UT cause new instance of Detector is created each time 'verify' executed.
       *
       * @throws Exception some Exception
       */
      @Test
      public void testStateIsBeingReset() throws Exception {
          final String illegal = "System\\.(out)|(err)\\.print(ln)?\\(";
          final TestLoggingReporter reporter = new TestLoggingReporter();
          final DetectorOptions detectorOptions = DetectorOptions.newBuilder()
                  .reporter(reporter)
                  .format(illegal)
                  .maximum(1)
                  .build();
  
          final SinglelineDetector detector =
                  new SinglelineDetector(detectorOptions);
          final File file = new File(getPath("InputRegexpSinglelineSemantic8.java"));
  
          detector.processLines(new FileText(file, StandardCharsets.UTF_8.name()));
          detector.processLines(new FileText(file, StandardCharsets.UTF_8.name()));
          assertWithMessage("Logged unexpected amount of issues")
                  .that(reporter.getLogCount())
                  .isEqualTo(0);
      }
  
      @Test
      public void testDefault() throws Exception {
          verifyWithInlineConfigParser(
                  getPath("InputRegexpSinglelineSemantic9.java"), EMPTY);
      }
  }
  