class TestGasStation(unittest.TestCase):
    def setUp(self):
        self.a_gas_station = GasStation(100, 2.0)

    def it_creates_a_gas_station(self):
        self.a_gas_station | should | be_instance_of(GasStation)

    def it_verify_the_state_of_the_fuel_pump(self):
        self.a_gas_station.maximum_capacity | should | be(100)
        self.a_gas_station.current_state | should | be(100)
        self.a_gas_station.price_per_liter | should | equal_to(2.0)

    def it_supply_the_vehicle(self):
        self.a_gas_station.supply(10) | should | equal_to(20.0)
        self.a_gas_station.current_state | should | be(90)
        self.a_gas_station.supply(10.0) | should | equal_to(5)
        self.a_gas_station.current_state | should | be(85)
        self.a_gas_station.supply("hi") | should | equal_to("Invalid Input")

    def it_refuel_the_pump(self):
        self.a_gas_station.refuel()
        self.a_gas_station.current_state | should | be(100)
 def setUp(self):
     self.a_gas_station = GasStation(100, 2.0)