@Test
public void should_read_two_instructions() {

    Circuit circuit = new Circuit(
            "123 -> x\n" +
                    "456 -> y");
    Map<Wire, SpecificValue> signals = circuit.signals();
    assertThat(signals).containsExactly(
            entry(new Wire("x"), new SpecificValue(123)),
            entry(new Wire("y"), new SpecificValue(456)));
}