@Test
    void child_injector_can_inject_multiple_instances_for_same_key() {
        Pair<Integer, Pair<Executor, Executor>> graph = buildGraphWithChildInjector(Executors::newSingleThreadExecutor);
        int graphSize = graph.getFirst();
        Executor executorA = graph.getSecond().getFirst();
        Executor executorB = graph.getSecond().getSecond();

        assertEquals(4, graphSize);
        assertNotSame(executorA, executorB);
    }
@author gjoranv
@author Tony Vaagenes
@author ollivir
container-core/src/test/java/com/yahoo/container/di/componentgraph/core/ComponentGraphTest.java