AdjacencyMap { public Set<Object> getAllSources() { return Collections.unmodifiableSet(edgeGraph.rowKeySet()); }  Set<Edge> getEdges(final Object source, final Object destination); Set<Edge> putEdges(final Object source, final Object destination, final Set<Edge> set); Set<Edge> putEdge(final Object source, final Object destination, final Edge edge); Set<Object> getDestinations(final Object source); Set<Object> getSources(final Object destination); Set<Object> getAllSources(); Set<Object> getAllDestinations(); void removeAllWithDestination(final Object destination); boolean containsSource(final Object source); boolean containsDestination(final Object destination); String toStringFull(); @Override String toString();  }
@Test public void shouldGetAllSources() { final AdjacencyMap adjacencyMap = getAdjacencyMap(); final Set<Object> results = adjacencyMap.getAllSources(); assertThat(results, hasItems(1, 2, 4, 5, 6)); }