1 * graph.getEdgeValues(1, 1, _) >> { args -> args[2] << '1->1' }
        0 * _._
        values == ['1', '1->1'] as Set
    }

    def collectsValuesWhenMultipleCyclesInGraph() {
        when:
        walker.add(1)
        def values = walker.findValues()

        then:
        1 * graph.getNodeValues(1, _, _) >> { args -> args[1] << '1'; args[2] << 1; args[2] << 2 }