public class MapClearTester<K, V> extends AbstractMapTester<K, V> {
  @MapFeature.Require(SUPPORTS_REMOVE)
  public void testClear() {
    getMap().clear();
    assertTrue("After clear(), a map should be empty.", getMap().isEmpty());
    assertEquals(0, getMap().size());
    assertFalse(getMap().entrySet().iterator().hasNext());
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_REMOVE})

            KerberosCredentials credentials = new KerberosCredentials(LOGIN_CONTEXT_NAME);
            KerberosKey foundKey = credentials.getKey(KEY_TYPE_1);
            assertNotNull(foundKey);
            assertEquals(key1, foundKey);
        }
    }

    /**
     * Test getKey method when the requested key type does not exist.
     *
     * @throws LoginException if login fails.
     */
    @Test

                writer.accept("\t--- init fork of " + fork.getKey() + " for " + mojoExecId + " ---");

                for (MojoExecution forkedExecution : fork.getValue()) {
                    mojo(writer, forkedExecution);
                }

                writer.accept("\t--- exit fork of " + fork.getKey() + " for " + mojoExecId + " ---");
            }
        }

        "getOrDefault(present, def) should return the associated value",
        v0(),
        getMap().getOrDefault(k0(), v3()));
  }

  @CollectionSize.Require(absent = ZERO)
  public void testGetOrDefault_presentNullDefault() {
    assertEquals(
        "getOrDefault(present, null) should return the associated value",
        v0(),
        getMap().getOrDefault(k0(), null));
  }

  public void testGetOrDefault_absent() {

        Objects.requireNonNull(model, "model cannot be null");

        ClassLoader parent = getMavenApiRealm();

        return createRealm(getKey(model), RealmType.Project, parent, null, null, artifacts);
    }

    private static String getKey(Model model) {
        return "project>" + model.getGroupId() + ":" + model.getArtifactId() + ":" + model.getVersion();
    }

    @Override

        decodedContext.decode(buffer, 0, buffer.length);

        // Verify decoded values
        assertArrayEquals(originalKey.getKey(), decodedContext.getLeaseKey().getKey());
        assertEquals(originalLeaseState, decodedContext.getLeaseState());
        assertEquals(originalScope, decodedContext.getCacheScope());
        assertEquals(60000L, decodedContext.getMaxCacheAge());

    private static <T> Map<AccessorKey, T> diff(Map<AccessorKey, T> first, Map<AccessorKey, T> second) {
        return first.entrySet().stream()
            .filter(e -> !second.containsKey(e.getKey()))
            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));
    }

    try {
      assertTrue(getMap().replace(k0(), v0(), v3()));
      expectReplacement(entry(k0(), v3()));
    } catch (ClassCastException tolerated) { // for ClassToInstanceMap
      expectUnchanged();
    }
  }

  @MapFeature.Require(SUPPORTS_PUT)
  @CollectionSize.Require(absent = ZERO)
  public void testReplaceEntry_supportedPresentUnchanged() {
    assertTrue(getMap().replace(k0(), v0(), v0()));

        v3(),
        getMap()
            .compute(
                k3(),
                (k, v) -> {
                  assertEquals(k3(), k);
                  assertNull(v);
                  return v3();
                }));
    expectAdded(e3());
    assertEquals(getNumElements() + 1, getMap().size());
  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE})

        v3(),
        getMap()
            .compute(
                k3(),
                (k, v) -> {
                  assertEquals(k3(), k);
                  assertNull(v);
                  return v3();
                }));
    expectAdded(e3());
    assertEquals(getNumElements() + 1, getMap().size());
  }

  @MapFeature.Require({SUPPORTS_PUT, SUPPORTS_REMOVE})