@Override
    public Map<ExecutionAttemptID, ExecutionDeploymentState> getExecutionsOn(ResourceID host) {
        return executionsByHost.getOrDefault(host, Collections.emptySet()).stream()
                .collect(
                        Collectors.toMap(
                                x -> x,
                                x ->
                                        pendingDeployments.contains(x)
                                                ? ExecutionDeploymentState.PENDING
                                                : ExecutionDeploymentState.DEPLOYED));
    }
@Test
    void testGetExecutionsReturnsEmptySetForUnknownHost() {
        final DefaultExecutionDeploymentTracker tracker = new DefaultExecutionDeploymentTracker();

        assertThat(tracker.getExecutionsOn(ResourceID.generate()).entrySet()).isEmpty();
    }