@Test
    void providers_can_be_injected_explicitly() {
        ComponentGraph componentGraph = new ComponentGraph();

        Node componentTakingExecutor = mockComponentNode(ComponentTakingExecutor.class);
        Node executorProvider = mockComponentNode(ExecutorProvider.class);
        componentTakingExecutor.inject(executorProvider);

        componentGraph.add(executorProvider);
        componentGraph.add(mockComponentNode(ExecutorProvider.class));

        componentGraph.add(componentTakingExecutor);

        componentGraph.complete();
        assertNotNull(componentGraph.getInstance(ComponentTakingExecutor.class));
    }
@author gjoranv
@author Tony Vaagenes
@author ollivir
container-core/src/test/java/com/yahoo/container/di/componentgraph/core/ComponentGraphTest.java