public static BackendExecutorContext getInstance() {
        return INSTANCE;
    }
@Test
    void assertGetInstance() {
        ContextManager contextManager = mockContextManager();
        when(ProxyContext.getInstance().getContextManager()).thenReturn(contextManager);
        assertThat(BackendExecutorContext.getInstance().getExecutorEngine(), is(BackendExecutorContext.getInstance().getExecutorEngine()));
    }