GitHub - barisx/CoveragableCode: You need to write coveragable code.

Coveragable Code Principle

You need to write coveragable code.

You have a code like:

print method is already coverage by tests in python source code. That means you can write a function with it like:

def say_hello():
    print("hello world")  # tested

Now you have a coveragable function. We need to write test for it. What if i write another function like:

def conversation():
    say_hello()  # assume that you did not write its test
    print("hi")  # tested

You write a function named as conversation and it has untested line. Coveragable Code Principle says:

You can not write a function with untested code parts.
All functions needs its test.
Every function can be valid if all sub lines tested before.

Lets fix conversation function with write tests with say_hello.

import unittest
from io import StringIO
import sys

# Functions
def say_hello():
    print("hello world")  # tested

def conversation():
    say_hello()  # tested
    print("hi")  # tested

# Test Case
class TestSayHello(unittest.TestCase):
    def test_say_hello(self):
        # Temporarily replace standard output
        capturedOutput = StringIO()
        sys.stdout = capturedOutput

        # Call the function
        say_hello()

        # Reset standard output
        sys.stdout = sys.__stdout__

        # Check if the function print "hello world" followed by a newline character
        self.assertEqual(capturedOutput.getvalue(), "hello world\n")

if __name__ == '__main__':
    unittest.main()

Now all is coveraged by tests. Now our last function conversation is coveragable.