codetutor/backend/data/questions/add-test-cases-prompt.md

Add Test Cases to Question Files - Context Prompt

Overview

This document provides context for adding function_signature and test_cases sections to question YAML files in the CodeTutor project.

Current Status

• Total question files: 401
• Files with test cases: 120
• Files needing test cases: ~281

File Location

All question files are in: /mnt/work/dev/portfolio/codetutor/backend/data/questions/

YAML Structure

Each question file should have function_signature and test_cases sections placed after the patterns section and before the description section.

Example Structure

title: Two Sum
slug: two-sum
difficulty: easy
leetcode_id: 1
leetcode_url: https://leetcode.com/problems/two-sum/
categories:
  - arrays
  - hash-tables
patterns:
  - two-pointers

function_signature: "def two_sum(nums: list[int], target: int) -> list[int]:"

test_cases:
  visible:
    - input: { nums: [2, 7, 11, 15], target: 9 }
      expected: [0, 1]
    - input: { nums: [3, 2, 4], target: 6 }
      expected: [1, 2]
    - input: { nums: [3, 3], target: 6 }
      expected: [0, 1]
  hidden:
    - input: { nums: [1, 5, 3, 7, 2], target: 10 }
      expected: [2, 3]
    - input: { nums: [-1, -2, -3, -4, -5], target: -8 }
      expected: [2, 4]
    - input: { nums: [0, 4, 3, 0], target: 0 }
      expected: [0, 3]

description: |
  Given an array of integers...

Function Signature Conventions

• Use Python type hints: list[int], str, int, bool, list[list[int]]
• Use snake_case for function and parameter names
• Match LeetCode's function signature where possible, but use Pythonic naming:
  • twoSum → two_sum
  • numCourses → num_courses
  • obstacleGrid → obstacle_grid

Special Types

For linked lists and trees, use:

• ListNode for linked list problems
• TreeNode for binary tree problems

Example:

function_signature: "def reorder_list(head: ListNode) -> None:"
function_signature: "def diameter_of_binary_tree(root: TreeNode) -> int:"

Test Case Guidelines

Visible Tests (2-3 cases)

• Include the examples from the problem description
• Cover basic happy path scenarios
• Keep inputs simple and easy to understand

Hidden Tests (5-7 cases)

• Edge cases: empty inputs, single elements, nulls
• Boundary conditions: min/max values, overflow scenarios
• Special patterns: all same values, strictly increasing/decreasing
• Negative numbers: if applicable
• Large inputs: for performance edge cases

Data Types in YAML

# Arrays
input: { nums: [1, 2, 3] }

# Strings (use quotes)
input: { s: "hello" }

# Nested arrays (matrices)
input: { grid: [[0, 0, 0], [0, 1, 0], [0, 0, 0]] }

# Multiple parameters
input: { nums: [1, 2, 3], target: 6 }

# Boolean expected values
expected: true
expected: false

# Linked lists (as arrays)
input: { head: [1, 2, 3, 4] }
expected: [1, 4, 2, 3]

# Trees (level-order with nulls)
input: { root: [1, 2, 3, null, 4] }

Finding Files Without Test Cases

Run this command to find files missing the function_signature:

cd /mnt/work/dev/portfolio/codetutor/backend/data/questions
for f in *.yaml; do
  if ! grep -q "^function_signature:" "$f"; then
    echo "$f"
  fi
done

Or use grep to count:

grep -L "^function_signature:" *.yaml | wc -l

Workflow

1. Read the problem file to understand:

   • The function parameters and return type
   • Example inputs/outputs from the examples section
   • Constraints for edge case ideas

2. Add the sections after patterns: and before description:

3. Verify YAML syntax - ensure proper indentation (2 spaces)

4. Commit in batches with message format:

   feat(content): add test cases for N additional problems
   

Priority Problems

Focus on commonly asked interview problems first:

• LeetCode Top 100
• Blind 75
• NeetCode 150

Categories Still Needing Coverage

Run this to see which files still need test cases:

grep -L "^function_signature:" *.yaml | head -50

Example: Adding Tests to a New File

Before (file without tests):

patterns:
  - sliding-window

description: |
  ...

After (file with tests):

patterns:
  - sliding-window

function_signature: "def max_sliding_window(nums: list[int], k: int) -> list[int]:"

test_cases:
  visible:
    - input: { nums: [1, 3, -1, -3, 5, 3, 6, 7], k: 3 }
      expected: [3, 3, 5, 5, 6, 7]
    - input: { nums: [1], k: 1 }
      expected: [1]
  hidden:
    - input: { nums: [9, 11], k: 2 }
      expected: [11]
    - input: { nums: [4, 3, 2, 1], k: 2 }
      expected: [4, 3, 2]
    - input: { nums: [7, 7, 7, 7], k: 3 }
      expected: [7, 7]

description: |
  ...

Changelog Update

After committing, update /mnt/work/dev/portfolio/codetutor/changelog.md:

## [Unreleased]

### Added

- Test cases for N additional questions bringing total to M:
  - Category: problem1, problem2, problem3
  - Category: problem4, problem5

Notes

• The test runner uses Pyodide (Python in WebAssembly) to execute code
• Visible tests run client-side; hidden tests are validated server-side
• Expected outputs must be JSON-serializable
• Order matters for list outputs unless the problem states "any order"