assert graph.getPlugins().contains("Z");
assert !graph.isComplete(error);
assert error.indexOf("[C]") > -1;
// reduce the graph - only 1,2,3,Z should be left since all of their required dependencies are satified
graph = graph.reduceGraph();
assert graph.getPlugins().size() == 4 : graph;
assert graph.getPlugins().contains("1") : graph;
assert graph.getPlugins().contains("2") : graph;
assert graph.getPlugins().contains("3") : graph;