Debug & Test
Debugging
偵錯
assert
assert <condition>, <message>
: 如果 condition 為 True,沒有作用;如果為 False,會產生錯誤,並顯示訊息
x = 5
assert x == 5, "x should be 5"
assert type(username) == str, "username must be a string"
Unit Test
單元測試
- 目的:以隔離主程式的方式,對自訂的函式(function)與方法(method),提供指定的輸入參數與期待的輸出結果,以驗證相關程式碼是否有瑕疵或錯誤。
- 方法:撰寫額外的測試用程式碼,並使用任一個單元測試模組,例如 unittest, Pytest 或類似用途的其他模組。
- 自動化:整合 CI/CD 做到全自動化程式碼單元測試
Pytest
unittest
Methods
.assertEqual(a, b)
: checks that a == b.assertNotEqual(a, b)
: checks that a != b.assertTrue('FOO'.isupper())
: checks that bool(x) is True.assertFalse('Foo'.isupper())
: checks that bool(x) is False
Example 1: rearrange.py
#!/usr/bin/env python3
import re
def rearrange_name(name):
result = re.search(r"^([\w .]*), ([\w .]*)$", name)
if result is None:
return name
return "{} {}".format(result[2], result[1])
rearrange_test.py :
#!/usr/bin/env python3
import unittest
from rearrange import rearrange_name
class TestRearrange(unittest.TestCase):
def test_basic(self): # Basic test case
testcase = "Lovelace, Ada"
expected = "Ada Lovelace"
self.assertEqual(rearrange_name(testcase), expected)
def test_empty(self): # Edge case, such as zero, blank, negative numbers, or extremely large numbers
testcase = ""
expected = ""
self.assertEqual(rearrange_name(testcase), expected)
def test_double_name(self): # Additional test case
testcase = "Hopper, Grace M."
expected = "Grace M. Hopper"
self.assertEqual(rearrange_name(testcase), expected)
def test_one_name(self): # Additional test case
testcase = "Voltaire"
expected = "Voltaire"
self.assertEqual(rearrange_name(testcase), expected)
# Run the tests
unittest.main()
Tip: 在 Jupyter 環境執行
unittest.main()
時可能會出現錯誤,修正方法是改成unittest.main(argv = ['first-arg-is-ignored'], exit = False))
。
The output of the result:
.
----------------------------------------------------------------------
Ran 4 test in 0.000s
OK
Example 2: cakefactory.py
#!/usr/bin/env python3
from typing import List
class CakeFactory:
def __init__(self, cake_type: str, size: str):
self.cake_type = cake_type
self.size = size
self.toppings = []
# Price based on cake type and size
self.price = 10 if self.cake_type == "chocolate" else 8
self.price += 2 if self.size == "medium" else 4 if self.size == "large" else 0
def add_topping(self, topping: str):
self.toppings.append(topping)
# Adding 1 to the price for each topping
self.price += 1
def check_ingredients(self) -> List[str]:
ingredients = ['flour', 'sugar', 'eggs']
ingredients.append('cocoa') if self.cake_type == "chocolate" else ingredients.append('vanilla extract')
ingredients += self.toppings
return ingredients
def check_price(self) -> float:
return self.price
# Example of creating a cake and adding toppings
cake = CakeFactory("chocolate", "medium")
cake.add_topping("sprinkles")
cake.add_topping("cherries")
cake_ingredients = cake.check_ingredients()
cake_price = cake.check_price()
cake_ingredients, cake_price
cakefactory_test.py
#!/usr/bin/env python3
import unittest
from cakefactory import CakeFactory
class TestCakeFactory(unittest.TestCase):
def test_create_cake(self):
cake = CakeFactory("vanilla", "small")
self.assertEqual(cake.cake_type, "vanilla")
self.assertEqual(cake.size, "small")
self.assertEqual(cake.price, 8) # Vanilla cake, small size
def test_add_topping(self):
cake = CakeFactory("chocolate", "large")
cake.add_topping("sprinkles")
self.assertIn("sprinkles", cake.toppings)
def test_check_ingredients(self):
cake = CakeFactory("chocolate", "medium")
cake.add_topping("cherries")
ingredients = cake.check_ingredients()
self.assertIn("cocoa", ingredients)
self.assertIn("cherries", ingredients)
self.assertNotIn("vanilla extract", ingredients)
def test_check_price(self):
cake = CakeFactory("vanilla", "large")
cake.add_topping("sprinkles")
cake.add_topping("cherries")
price = cake.check_price()
self.assertEqual(price, 13) # Vanilla cake, large size + 2 toppings
# Running the unittests
unittest.TextTestRunner().run(unittest.TestLoader().loadTestsFromTestCase(TestCakeFactory))
This results in the output:
..F.
======================================================================
FAIL: test_check_price (__main__.TestCakeFactory)
----------------------------------------------------------------------
Traceback (most recent call last):
File "<ipython-input-9-32dbf74b3655>", line 33, in test_check_price
self.assertEqual(price, 13) # Vanilla cake, large size + 2 toppings
AssertionError: 14 != 13
----------------------------------------------------------------------
Ran 4 tests in 0.007s
FAILED (failures=1)
<unittest.runner.TextTestResult run=4 errors=0 failures=1>
The program calls the TextTestRunner()
method, which returns a runner (TextTestResult
). It says one failure occurred: the statement self.assertEqual(price, 13)
was incorrect, as it should have been 14. How can we correct that part of the test? Update that part of the code to the following:
import unittest
# Fixing the test_check_price method
class TestCakeFactory(unittest.TestCase):
# ... Other tests remain the same
def test_check_price(self):
cake = CakeFactory("vanilla", "large")
cake.add_topping("sprinkles")
cake.add_topping("cherries")
price = cake.check_price()
self.assertEqual(price, 14) # Vanilla cake, large size + 2 toppings
# Re-running the unittests
unittest.TextTestRunner().run(unittest.TestLoader().loadTestsFromTestCase(TestCakeFactory))
And now the program works as expected, as the results provide no failures and are:
.
----------------------------------------------------------------------
Ran 4 test in 0.002s
OK
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