 testF(SwitchesFixture, testPressingASingleButton) {
     switches.initialise(&mockIo, true);
     switches.addSwitch(2, onSwitchPressed, NO_REPEAT);
+    switches.onRelease(2, onSwitchReleased);
     assertFalse(switches.isInterruptDriven());
 
     // simulate the button being pressed (with a bounce).

    mockIo.resetIo();
    for(int i=0; i<25;i++)  mockIo.setValueForReading(i, 0x0000);
    assertHeldState(true);

    // make sure getting to held took near to 400 millis.
    assertMoreOrEqual(millis() - millisStart, (uint32_t)380);

    // we now simulate the button being pressed down.
    for(int i=3; i<25;i++)  mockIo.setValueForReading(i, 0x0000);
    assertPressedState(true);
    assertFalse(keyReleased);

    long millisStart = millis();

