for (long a : TEST_LONGS) {
      assertThrows(
          ArithmeticException.class,
          () -> UnsignedLong.fromLongBits(a).dividedBy(UnsignedLong.ZERO));
    }
  }

  public void testMod() {
    for (long a : TEST_LONGS) {
      for (long b : TEST_LONGS) {
        if (b != 0) {
          UnsignedLong aUnsigned = UnsignedLong.fromLongBits(a);

    for (long a : TEST_LONGS) {
      assertThrows(
          ArithmeticException.class,
          () -> UnsignedLong.fromLongBits(a).dividedBy(UnsignedLong.ZERO));
    }
  }

  public void testMod() {
    for (long a : TEST_LONGS) {
      for (long b : TEST_LONGS) {
        if (b != 0) {
          UnsignedLong aUnsigned = UnsignedLong.fromLongBits(a);

        assertFalse(robotsTxt.allows("/valid1/", "TestBot"));
        assertFalse(robotsTxt.allows("/valid2/", "TestBot"));
        assertTrue(robotsTxt.allows("/valid3/", "TestBot"));
        assertFalse(robotsTxt.allows("/valid4/", "TestBot"));
    }

    public void testParse_emptyValues() {
        String robotsTxtContent = "User-agent: TestBot\n" + "Disallow:\n" + "Allow:\n" + "Crawl-delay:\n";

## Testing Best Practices

1. **Isolation**: Each test is independent and doesn't affect others
2. **Clarity**: Test names clearly describe what is being tested
3. **Coverage**: Both success and failure paths are tested
4. **Edge Cases**: Null, empty, and boundary conditions are covered
5. **Resources**: Test resources are properly managed and cleaned up

## Contributing

When adding new tests:

  }

  public void testContainsRow() {
    assertFalse(INSTANCE.containsRow('a'));
  }

  public void testContainsValue() {
    assertFalse(INSTANCE.containsValue("blah"));
  }

  public void testRow() {
    assertEquals(ImmutableMap.of(), INSTANCE.row('a'));
  }

  public void testRowKeySet() {
    assertEquals(ImmutableSet.of(), INSTANCE.rowKeySet());
  }

  public void testRowMap() {

  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

  /** Creates and returns an instance of the graph to be tested. */
  abstract Graph<Integer> createGraph();

  /**
   * A proxy method that adds the node {@code n} to the graph being tested. In case of Immutable
   * graph implementations, this method should replace {@link #graph} with a new graph that includes
   * this node.
   */

    assertEquals(ImmutableSet.of(1), testTable.columnKeySet());
  }

  public void testColumnMap() {
    assertEquals(ImmutableMap.of(1, ImmutableMap.of('a', "blah")), testTable.columnMap());
  }

  public void testRow() {
    assertEquals(ImmutableMap.of(), testTable.row('A'));
    assertEquals(ImmutableMap.of(1, "blah"), testTable.row('a'));
  }

  public void testRowKeySet() {

  static final String ERROR_ADDED_SELF_LOOP = "Should not be allowed to add a self-loop edge.";

  /** Creates and returns an instance of the graph to be tested. */
  abstract Graph<Integer> createGraph();

  /**
   * A proxy method that adds the node {@code n} to the graph being tested. In case of Immutable
   * graph implementations, this method should replace {@link #graph} with a new graph that includes
   * this node.
   */

import org.jspecify.annotations.NullUnmarked;

/**
 * Unit test for {@link Files}.
 *
 * <p>Some methods are tested in separate files:
 *
 * <ul>
 *   <li>{@link Files#fileTraverser()} is tested in {@link FilesFileTraverserTest}.
 *   <li>{@link Files#createTempDir()} is tested in {@link FilesCreateTempDirTest}.
 * </ul>
 *
 * @author Chris Nokleberg
 */

import org.jspecify.annotations.NullUnmarked;

/**
 * Unit test for {@link Files}.
 *
 * <p>Some methods are tested in separate files:
 *
 * <ul>
 *   <li>{@link Files#fileTraverser()} is tested in {@link FilesFileTraverserTest}.
 *   <li>{@link Files#createTempDir()} is tested in {@link FilesCreateTempDirTest}.
 * </ul>
 *
 * @author Chris Nokleberg
 */