Context { public String get(String key) { Preconditions.checkNotNull(key, "key is null"); return values.get(key); }  Set<String> getKeys(); String get(String key); void put(String key, String value); Map<String, Context> getChildren(); Context getChild(String name); Context createChild(String name); void remove(String nameOrKey); void setId(String id); String getId(); @Override String toString();  }
@Test public void testGetNonExistingKey_shouldReturnNull() throws Exception { assertThat(context.get("non-existing"), nullValue()); }