public void vertexFinished(final ExecutionVertexID executionVertexId) {
        assertVertexInRegion(executionVertexId);
        unfinishedVertices.remove(executionVertexId);
    }
@Test
    public void finishingUnknownVertexThrowsException() {
        final PipelinedRegionExecutionView pipelinedRegionExecutionView =
                new PipelinedRegionExecutionView(TEST_PIPELINED_REGION);

        final ExecutionVertexID unknownVertexId = new ExecutionVertexID(new JobVertexID(), 0);
        assertThatThrownBy(() -> pipelinedRegionExecutionView.vertexFinished(unknownVertexId))
                .isInstanceOf(IllegalArgumentException.class);
    }