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;
  
  import static com.google.common.truth.Truth.assertWithMessage;
  import static com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck.MSG_KEY_NO_NEWLINE_EOF;
  import static com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck.MSG_KEY_UNABLE_OPEN;
  import static com.puppycrawl.tools.checkstyle.checks.NewlineAtEndOfFileCheck.MSG_KEY_WRONG_ENDING;
  
  import java.io.File;
  import java.io.FileNotFoundException;
  import java.io.RandomAccessFile;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Set;
  
  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.api.FileText;
  import com.puppycrawl.tools.checkstyle.api.Violation;
  import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
  import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
  
  public class NewlineAtEndOfFileCheckTest
      extends AbstractModuleTestSupport {
  
      @Override
      protected String getPackageLocation() {
          return "com/puppycrawl/tools/checkstyle/checks/newlineatendoffile";
      }
  
      @Test
      public void testNewlineLfAtEndOfFile() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileLf.java"),
              expected);
      }
  
      @Test
      public void testNewlineLfAtEndOfFileLfNotOverlapWithCrLf() throws Exception {
          final String[] expected = {
              "1: " + getCheckMessage(MSG_KEY_WRONG_ENDING),
          };
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileCrlf.java"),
              expected);
      }
  
      @Test
      public void testNewlineCrlfAtEndOfFile() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileCrlf3.java"),
              expected);
      }
  
      @Test
      public void testNewlineCrAtEndOfFile() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileCr.java"),
              expected);
      }
  
      @Test
      public void testAnyNewlineAtEndOfFile() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileCrlf2.java"),
              expected);
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileLf2.java"),
              expected);
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileCr2.java"),
              expected);
      }
  
      @Test
      public void testNoNewlineLfAtEndOfFile() throws Exception {
          final String[] expected = {
              "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
          };
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileNoNewline.java"),
              expected);
      }
  
      @Test
      public void testNoNewlineAtEndOfFile() throws Exception {
          final String msgKeyNoNewlineEof = "File does not end with a newline :)";
          final String[] expected = {
              "1: " + msgKeyNoNewlineEof,
          };
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileNoNewline2.java"),
              expected);
      }
  
      @Test
      public void testSetLineSeparatorFailure()
              throws Exception {
          final DefaultConfiguration checkConfig =
              createModuleConfig(NewlineAtEndOfFileCheck.class);
          checkConfig.addProperty("lineSeparator", "ct");
          try {
              createChecker(checkConfig);
              assertWithMessage("exception expected").fail();
          }
          catch (CheckstyleException ex) {
              assertWithMessage("Error message is unexpected")
                      .that(ex.getMessage())
                      .isEqualTo("cannot initialize module com.puppycrawl.tools.checkstyle."
                              + "checks.NewlineAtEndOfFileCheck - "
                              + "Cannot set property 'lineSeparator' to 'ct'");
          }
      }
  
      @Test
      public void testEmptyFileFile() throws Exception {
          final DefaultConfiguration checkConfig =
              createModuleConfig(NewlineAtEndOfFileCheck.class);
          checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF.toString());
          final String[] expected = {
              "1: " + getCheckMessage(MSG_KEY_NO_NEWLINE_EOF),
          };
          verify(
              checkConfig,
              getPath("InputNewlineAtEndOfFileEmptyFile.txt"),
              expected);
      }
  
      @Test
      public void testFileWithEmptyLineOnly() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(NewlineAtEndOfFileCheck.class);
          checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF.toString());
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(
                  checkConfig,
                  getPath("InputNewlineAtEndOfFileNewlineAtEnd.txt"),
                  expected);
      }
  
      @Test
      public void testFileWithEmptyLineOnlyWithLfCrCrlf() throws Exception {
          final DefaultConfiguration checkConfig =
                  createModuleConfig(NewlineAtEndOfFileCheck.class);
          checkConfig.addProperty("lineSeparator", LineSeparatorOption.LF_CR_CRLF.toString());
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verify(
                  checkConfig,
                  getPath("InputNewlineAtEndOfFileNewlineAtEndLf.txt"),
                  expected);
      }
  
      @Test
      public void testWrongFile() throws Exception {
          final DefaultConfiguration checkConfig = createModuleConfig(NewlineAtEndOfFileCheck.class);
          final NewlineAtEndOfFileCheck check = new NewlineAtEndOfFileCheck();
          check.configure(checkConfig);
          final List<String> lines = new ArrayList<>(1);
          lines.add("txt");
          final File impossibleFile = new File("");
          final FileText fileText = new FileText(impossibleFile, lines);
          final Set<Violation> violations = check.process(impossibleFile, fileText);
          assertWithMessage("Amount of violations is unexpected")
                  .that(violations)
                  .hasSize(1);
          final Iterator<Violation> iterator = violations.iterator();
          assertWithMessage("Violation message differs from expected")
                  .that(iterator.next().getViolation())
                  .isEqualTo(getCheckMessage(MSG_KEY_UNABLE_OPEN, ""));
      }
  
      @Test
      public void testWrongSeparatorLength() throws Exception {
          try (RandomAccessFile file =
                       new ReadZeroRandomAccessFile(getPath("InputNewlineAtEndOfFileLf.java"), "r")) {
              TestUtil.invokeMethod(new NewlineAtEndOfFileCheck(), "endsWithNewline", file,
                  LineSeparatorOption.LF);
              assertWithMessage("ReflectiveOperationException is expected").fail();
          }
          catch (ReflectiveOperationException ex) {
              assertWithMessage("Error message is unexpected")
                  .that(ex)
                      .hasCauseThat()
                          .hasMessageThat()
                          .isEqualTo("Unable to read 1 bytes, got 0");
          }
      }
  
      @Test
      public void testTrimOptionProperty() throws Exception {
          final String[] expected = CommonUtil.EMPTY_STRING_ARRAY;
          verifyWithInlineConfigParser(
                  getPath("InputNewlineAtEndOfFileTestTrimProperty.java"),
                  expected);
      }
  
      private static final class ReadZeroRandomAccessFile extends RandomAccessFile {
  
          private ReadZeroRandomAccessFile(String name, String mode)
                  throws FileNotFoundException {
              super(name, mode);
          }
  
          @Override
          public int read(byte[] bytes) {
              return 0;
          }
      }
  
  }
  