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Demo

git-gamble's demo to develop using TCRDD by doing baby steps

On a simple program

git-gamble works with all languages and tools and editor ; this example uses python with pytest and nano

export GAMBLE_TEST_COMMAND='pytest --quiet'

Note : for a simpler demo, test code and production code are in the same file

Alternatively : you can also watch the slides about the demo

First TDD loop ➰

Write a program that says Hello world

First, 🔴 Red phase : write a test that fails for the good reason

Alternative text 
nano test_hello.py

def hello():
    pass

def test_say_hello_world():
    assert hello() == 'Hello world'

Then, gamble that the tests fail

git gamble --red

Committed

Second, 🟢 Green phase : write the minimum code to pass the tests

Let's fake it

Alternative text 
nano test_hello.py

def hello():
    return 'Hello word'

Then, gamble that the tests pass

git gamble --green

Reverted

Oh no !

I made a typo

 def hello():
-    return 'Hello word'
+    return 'Hello world'

Try again

Let's fake it without typo

Alternative text 
nano test_hello.py

def hello():
    return 'Hello world'

Gamble again that the tests pass

git gamble --green

Committed

Yeah !

Third, 🔀 Refactor phase : Nothing to refactor yet

Then 🔁 Repeat ➰

Second TDD loop ➿

Write a program that says Hello to the given name when a name is given

🔴 Red phase

Alternative text 
nano test_hello.py

def test_say_hello_name_given_a_name():
    assert hello('Jon') == 'Hello Jon'

git gamble --red

Committed

🟢 Green phase

Add a simple condition to handle both cases

Alternative text 
nano test_hello.py

def hello(arg=None):
    if arg:
        return f'Hello {arg}'
    return 'Hello world'

git gamble --green

Committed

🔀 Refactor loop ➰

🔀 Refactor phase

It can be simplified

Alternative text 
nano test_hello.py

def hello(arg='world'):
    return f'Hello {arg}'

git gamble --refactor

Committed

Still 🔀 Refactor phase : i have something else to refactor ➿

Better naming

Alternative text 
nano test_hello.py

def hello(name='world'):
    return f'Hello {name}'

git gamble --refactor

Committed

And so on... ➿

🔁 Repeat until you have tested all the rules, are satisfied and enougth confident