public void PopulateStartingContextParameters_CalledWithStartingParameters() { Graph graph = new Graph(); GraphContextParameter startingParameter = new GraphContextParameter { type = GraphContextParameterType.Int, key = "Key" }; graph.AddStartingContextParameter(startingParameter); IGraphContext mockContext = Substitute.For <IGraphContext>(); IGraphContextFactory stubFactory = Substitute.For <IGraphContextFactory>(); stubFactory.MakeContext().Returns(mockContext); GraphContextFactoryLocator.Provide(stubFactory); graph.Start(); mockContext.Received().PopulateStartingContextParameters(Arg.Is <IList <GraphContextParameter> >(list => list.Contains(startingParameter))); }