Mural.co technical interview test

Let's play tic-tac-toe.

Goals

This test should serve as a basis for the technical evaluation of a candidate

Skillset

Here's a typical breakdown of how much time should be spent on each skill we are probing for.

Skill	Time
Unit testing	25%
Design patterns	25%
Data structures	20%
Web semantics	15%
React	15%

1. Unit testing

1. Add one simple unit test

1. You can only play in a empty square (~10min)
2. You can't play when the game has ended
3. You can only place a single Ω piece per game
4. You can't play when the AI is thinking

2. Add one complex unit test

1. Winning end-game test (programatic/property-based testing) (~20min)

For a board of M×M size, there are 2+2*M possible solutions But how do you test the rest?

Q&A: Is this exhaustive?

2. AI should play randomly (requires mocking random)

• seed works

2. Design patterns/algorithms

1. Implement a move recorder (encoding) with chess notation 123,abc (~15-30min)

2. Implement a new piece behavior

3. Implement a parametric board size

4. Q&A to test for the patterns that existed in the codebase

• AI Implementation (visitor)
• Creating the board (factory)
• Pick your AI implementation (strategy)
• Undo feature (memento)
• De-duplicating the board state (flyweight)

3. Data structures

1. Board structure
2. Piece definition (x)
3. Piece behavior
4. Game state (x)

4. Web semantics

Proper usage of HTML landmarks

• <img alt /> attributes for images
• <p />
• <section />

4.1 HTML Scaffolding

1. Implement the UI design (~15min)

4.2 ARIA/A11y

1. Implement a11y features usage of ARIA/fallback attributes (~15min)

• Tab index for all the cells (x)
• Screen reader feedback for focusing a cell
• Screen reader feedback for piece placement

5. React

Implement the rendering logic

• Rendering elements
• Game state/reset
• User interactions
• Async components (AI thinking…)

1. Implement AI thinking behavior (code) (~30min)
2. Implement error messages handling (code)