def test_alien_teleport_method(self):
alien = Alien(0, 0)
alien.teleport(-1, -4)
error = (
"Expected alien to be at position (-1, -4) but "
f"instead found it in position {(alien.x_coordinate, alien.y_coordinate)}.")
self.assertEqual((-1, -4), (alien.x_coordinate, alien.y_coordinate), msg=error)
def test_alien_class_variable(self):
alien_one = Alien(0, 2)
alien_two = Alien(-6, -1)
Alien.total_aliens_created = -2
error_one = "Expected the total_aliens_created variable to be identical."
error_two = "Expected the health variable to be identical."
self.assertEqual(alien_two.total_aliens_created, alien_one.total_aliens_created, msg=error_one)
self.assertEqual(alien_two.health, alien_one.health, msg=error_two)
def test_alien_instance_variables(self):
alien_one = Alien(-8, -1)
alien_two = Alien(2, 5)
coord_x_error = ("Expected alien_one and alien_two to have different x "
f"positions. Instead both x's were: {alien_two.x_coordinate}.")
coord_y_error = ("Expected alien_one and alien_two to have different y "
f"positions. Instead both y's were: {alien_two.y_coordinate}.")
self.assertFalse(alien_one.x_coordinate == alien_two.x_coordinate, msg=coord_x_error)
self.assertFalse(alien_one.y_coordinate == alien_two.y_coordinate, msg=coord_y_error)
def test_alien_hit_method(self):
# There are two valid interpretations for this method/task.
# `self.health -= 1` and `self.health = max(0, self.health - 1)`
# The tests for this task reflect this ambiguity.
data = [(1, (2,)), (2, (1,)), (3, (0,)), (4, (0, -1)), (5, (0, -2)), (6, (0, -3))]
for variant, (iterations, result) in enumerate(data, 1):
alien = Alien(2, 2)
with self.subTest(f'variation #{variant}', input=iterations, output=result):
error = ("Expected hit method to decrement health by 1. "
f"Health is {alien.health} when it should be {result}.")
for _ in range(iterations):
alien.hit()
self.assertIn(alien.health, result, msg=error)
def test_alien_total_aliens_created(self):
Alien.total_aliens_created = 0
aliens = [Alien(-2, 6)]
error = ("Expected total_aliens_created to equal 1. Instead "
f"it equals: {aliens[0].total_aliens_created}.")
self.assertEqual(1, aliens[0].total_aliens_created, msg=error)
aliens.append(Alien(3, 5))
aliens.append(Alien(-5, -5))
def error_text(alien, variable):
return (
"Expected all total_aliens_created variables to be "
"equal to number of alien instances (i.e. 3). Alien "
f"number {alien}'s total_aliens_created variable "
f"is equal to {variable}.")
tac_list = [alien.total_aliens_created for alien in aliens]
self.assertEqual(3, tac_list[0], msg=error_text(1, tac_list[0]))
self.assertEqual(3, tac_list[1], msg=error_text(2, tac_list[1]))
self.assertEqual(3, tac_list[2], msg=error_text(3, tac_list[2]))
def test_alien_is_alive_method(self):
alien = Alien(0, 1)
alive_error = "Alien is dead while health is greater than 0."
dead_error = "Alien is alive while health is less than or equal to 0."
for _ in range(5):
alien.hit()
if alien.health > 0:
self.assertTrue(alien.is_alive(), msg=alive_error)
else:
self.assertFalse(alien.is_alive(), msg=dead_error)
def test_alien_collision_detection_method(self):
alien = Alien(7, 3)
error = "Expected collision_detection method to not be implemented."
self.assertIsNone(alien.collision_detection(Alien(7, 2)), msg=error)
def test_alien_has_health(self):
alien = Alien(0, 0)
error = ("Expected object's health to be 3 but instead found "
f"it had a health of {alien.health}.")
self.assertEqual(3, alien.health, msg=error)
def test_alien_has_correct_initial_coordinates(self):
alien = Alien(2, -1)
error = ("Expected object to be at position (2, -1) but instead "
f"found it initialized to position {(alien.x_coordinate, alien.y_coordinate)}.")
self.assertEqual((2, -1), (alien.x_coordinate, alien.y_coordinate), msg=error)