Map<String, Object> map = new HashMap<>();
        map.put("key", "value");
        map.put("nullKey", null);

        assertTrue(MapValueExtractor.hasValue(map, "key"));
        assertFalse(MapValueExtractor.hasValue(map, "nullKey"));
        assertFalse(MapValueExtractor.hasValue(map, "missing"));
    }

  public void testToOptionalEmpty() {
    assertThat(Stream.empty().collect(toOptional())).isEmpty();
  }

  public void testToOptionalSingleton() {
    assertThat(Stream.of(1).collect(toOptional())).hasValue(1);
  }

  public void testToOptionalNull() {
    Stream<@Nullable Object> stream = Stream.of((Object) null);
    assertThrows(NullPointerException.class, () -> stream.collect(toOptional()));
  }

        @SuppressWarnings({"unchecked", "nullness"})
        K castKey = (K) key;
        @SuppressWarnings({"unchecked", "nullness"}) // similar to the above
        V castValue = (V) value;

        alertListenerIfPresent(castKey, castValue, RemovalCause.EXPLICIT);
        remove(key);
        return true;
      }
      return false;
    }
  }

  @Override

  }

  public void testTryFind() {
    Iterable<String> list = newArrayList("cool", "pants");
    assertThat(tryFind(list, equalTo("cool"))).hasValue("cool");
    assertThat(tryFind(list, equalTo("pants"))).hasValue("pants");
    assertThat(tryFind(list, Predicates.alwaysTrue())).hasValue("cool");
    assertThat(tryFind(list, Predicates.alwaysFalse())).isAbsent();
    assertCanIterateAgain(list);
  }

    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("cool"))).hasValue("cool");
  }

  public void testTryFind_lastElement() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("pants"))).hasValue("pants");
  }

  public void testTryFind_alwaysTrue() {

     *
     * @param map The source map
     * @param key The key to check
     * @return true if the key exists and its value is not null
     */
    public static boolean hasValue(final Map<String, Object> map, final String key) {
        return map.containsKey(key) && map.get(key) != null;
    }

    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("cool"))).hasValue("cool");
  }

  public void testTryFind_lastElement() {
    Iterable<String> list = Lists.newArrayList("cool", "pants");
    Iterator<String> iterator = list.iterator();
    assertThat(tryFind(iterator, equalTo("pants"))).hasValue("pants");
  }

  public void testTryFind_alwaysTrue() {

org.apache.maven.wrapper.cli; public synchronized class ParsedCommandLineOpt { private final java.util.List values; public void ParsedCommandLineOpt(); public String getValue(); public java.util.List getValues(); public void addArgument(String); public boolean hasValue(); } org/apache/maven/wrapper/cli/ProjectPropertiesCom.class package org.apache.maven.wrapper.cli; public synchronized class ProjectPropertiesCom extends AbstractPropertiesCo { public void ProjectPropertiesCom(); protected String getPropertyOption();...

    }

    directedGraph.addEdge(N2, N1, E21);
    // View should be updated.
    assertThat(transpose.edgesConnecting(N1, N2)).containsExactly(E21);
    assertThat(transpose.edgeConnecting(N1, N2)).hasValue(E21);
    assertThat(transpose.edgeConnectingOrNull(N1, N2)).isEqualTo(E21);
    AbstractNetworkTest.validateNetwork(transpose);
  }

  @Test
  public void inducedSubgraph_graph() {