TDD as if you Meant It: Think – Red – Green – Refactor (Episode 1)

About

TDD as if you meant it is a very strict way of writing code in a Test Driven Development approach. One needs to follow the rules below:

Guidelines

In the first episode the main focus in to respect a few guidelines:

1. Guideline 1: Always start with outputs when doing an analysis
2. Guideline 2: Behavior Slicing
3. Guideline 3: SIMPLIFY!
4. Guideline 4: Introduce only one notion (domain concept) at a time, one per test
5. Guideline 5: The rule of three “only extract duplication when spotted at least three times”
6. Guideline 6: Triangulation

Think

The most important thing with TDD is to think before starting to code. So I introduced this step and I am using the cycle

Think -> Red -> Green -> Refactor

We do need analysis before writing code and before using Test Driven Development!

Tests

Based on these guidelines I started writing some tests, while simplifying to the maximum the problem.

My first test is about the simplest Tic Tac Toe game: X always wins on a one by one board

    @Test
    public void forOneByOneBoardXAlwaysWins(){
        // Arrange
        String board = "one by one";
        String expected = "X won";

        // Production code
        String gameResult = board == "one by one" ? "X won" : "Nobody won";

        // Act
        String actual = gameResult;

        // Assert
        assertEquals(expected, actual);
    }

 

Then I started triangulating on the notion of winning

    @Test
    public void forTwoByTwoBoardXWinsOnLeftColumn(){
        // Arrange
        String board = "two by two with X on left column";
        String expected = "X won";

        // Production code
        String gameResult = board == "two by two with X on left column" ? "X won" : "Nobody won";

        // Act
        String actual = gameResult;

        // Assert
        assertEquals(expected, actual);
    }

    @Test
    public void forTwoByTwoBoardXWinsOnRightColumn(){
        // Arrange
        String board = "two by two with X on right column";
        String expected = "X won";

        // Production code
        String gameResult = board == "two by two with X on right column" ? "X won" : "Nobody won";

        // Act
        String actual = gameResult;

        // Assert
        assertEquals(expected, actual);
    }

Video

Check the video below with the first episode:

What’s Next?

Check the next episode on TDD as if you Meant it here: http://blog.adrianbolboaca.ro/evolutionary-design

On the same page you can find more ideas on Evolutionary Design.

Credits

Many thanks to Keith Braithwaite for creating the concept of TDD as if you Meant It

Teddy bear thanks to Erik Talboom for all the pairing, discussions that lead to so many twists we discovered together with TDD as if you Meant It.

Special regards to JB Rainsberger for the fun pairing we did using TDD as if you Meant It

 

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