diff --git a/unit-testing.html b/unit-testing.html index 117e42c..80010e3 100755 --- a/unit-testing.html +++ b/unit-testing.html @@ -130,7 +130,7 @@ if __name__ == '__main__':
  • To write a test case, first subclass the TestCase class of the unittest module. This class provides many useful methods which you can use in your test case to test specific conditions.
  • This is a list of integer/numeral pairs that I verified manually. It includes the lowest ten numbers, the highest number, every number that translates to a single-character Roman numeral, and a random sampling of other valid numbers. You don’t need to test every possible input, but you should try to test all the obvious edge cases.
  • Every individual test is its own method, which must take no parameters and return no value. If the method exits normally without raising an exception, the test is considered passed; if the method raises an exception, the test is considered failed. -
  • Here you call the actual to_roman() function. (Well, the function hasn’t be written yet, but once it is, this is the line that will call it.) Notice that you have now defined the API for the to_roman() function: it must take an integer (the number to convert) and return a string (the Roman numeral representation). If the API is different than that, this test is considered failed. Also notice that you are not trapping any exceptions when you call to_roman(). This is intentional. to_roman() shouldn’t raise an exception when you call it with valid input, and these input values are all valid. If to_roman() raises an exception, this test is considered failed. +
  • Here you call the actual to_roman() function. (Well, the function hasn’t been written yet, but once it is, this is the line that will call it.) Notice that you have now defined the API for the to_roman() function: it must take an integer (the number to convert) and return a string (the Roman numeral representation). If the API is different than that, this test is considered failed. Also notice that you are not trapping any exceptions when you call to_roman(). This is intentional. to_roman() shouldn’t raise an exception when you call it with valid input, and these input values are all valid. If to_roman() raises an exception, this test is considered failed.
  • Assuming the to_roman() function was defined correctly, called correctly, completed successfully, and returned a value, the last step is to check whether it returned the right value. This is a common question, and the TestCase class provides a method, assertEqual, to check whether two values are equal. If the result returned from to_roman() (result) does not match the known value you were expecting (numeral), assertEqual will raise an exception and the test will fail. If the two values are equal, assertEqual will do nothing. If every value returned from to_roman() matches the known value you expect, assertEqual never raises an exception, so test_to_roman_known_values eventually exits normally, which means to_roman() has passed this test.