Graph graph = new Graph();
        graph.addEdge("a1", "a2");
        assertThrows(Graph.CycleDetectedException.class, () -> graph.addEdge("a2", "a1"));
    }

    @Test
    public void testPerf() throws IOException {
        List<String[]> data = new ArrayList<>();
        String k = null;
        for (String line : Files.readAllLines(Paths.get("src/test/resources/dag.txt"))) {
            if (line.startsWith("\t")) {

  public void testNullEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    assertThrows(NullPointerException.class, () -> tester.addEqualityGroup((Object[]) null));
  }

  public void testNullObjectInEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    NullPointerException e =
        assertThrows(NullPointerException.class, () -> tester.addEqualityGroup(1, null, 3));

  public void testNullEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    assertThrows(NullPointerException.class, () -> tester.addEqualityGroup((Object[]) null));
  }

  public void testNullObjectInEqualityGroup() {
    EqualsTester tester = new EqualsTester();
    NullPointerException e =
        assertThrows(NullPointerException.class, () -> tester.addEqualityGroup(1, null, 3));

    List<Class<? extends AbstractTester>> testers = copyToList(super.getTesters());

    testers.add(CollectionSerializationEqualTester.class);
    testers.add(SetAddAllTester.class);
    testers.add(SetAddTester.class);
    testers.add(SetCreationTester.class);
    testers.add(SetHashCodeTester.class);
    testers.add(SetEqualsTester.class);
    testers.add(SetRemoveTester.class);

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * This abstract base class for testers allows the framework to inject needed information after
 * JUnit constructs the instances.
 *
 * <p>This class is emulated in GWT.
 *
 * @param <G> the type of the test generator required by this tester. An instance of G should
 *     somehow provide an instance of the class under test, plus any other information required to

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * This abstract base class for testers allows the framework to inject needed information after
 * JUnit constructs the instances.
 *
 * <p>This class is emulated in GWT.
 *
 * @param <G> the type of the test generator required by this tester. An instance of G should
 *     somehow provide an instance of the class under test, plus any other information required to

    testers.add(ListHashCodeTester.class);
    testers.add(ListIndexOfTester.class);
    testers.add(ListLastIndexOfTester.class);
    testers.add(ListListIteratorTester.class);
    testers.add(ListRemoveAllTester.class);
    testers.add(ListRemoveAtIndexTester.class);
    testers.add(ListRemoveTester.class);
    testers.add(ListReplaceAllTester.class);
    testers.add(ListRetainAllTester.class);
    testers.add(ListSetTester.class);

    List<Class<? extends AbstractTester>> testers = copyToList(super.getTesters());
    testers.add(CollectionSerializationEqualTester.class);
    testers.add(MultisetAddTester.class);
    testers.add(MultisetContainsTester.class);
    testers.add(MultisetCountTester.class);
    testers.add(MultisetElementSetTester.class);
    testers.add(MultisetEqualsTester.class);
    testers.add(MultisetForEachEntryTester.class);

import static com.google.common.collect.testing.testers.CollectionAddAllTester.getAddAllNullUnsupportedMethod;
import static com.google.common.collect.testing.testers.CollectionAddTester.getAddNullSupportedMethod;
import static com.google.common.collect.testing.testers.CollectionAddTester.getAddNullUnsupportedMethod;
import static com.google.common.collect.testing.testers.CollectionCreationTester.getCreateWithNullUnsupportedMethod;

    List<Class<? extends AbstractTester>> testers = copyToList(super.getTesters());
    testers.add(SetMultimapAsMapTester.class);
    testers.add(SetMultimapEqualsTester.class);
    testers.add(SetMultimapPutTester.class);
    testers.add(SetMultimapPutAllTester.class);
    testers.add(SetMultimapReplaceValuesTester.class);
    return testers;
  }

  @Override
  TestSuite computeMultimapGetTestSuite(