Running Tests

Test Framework

This project uses Jest as the testing framework with SWC for fast TypeScript transpilation. Every data structure and algorithm includes comprehensive test coverage.

Running All Tests

To run the complete test suite:

npm test

This command will:

Compile all TypeScript files using tsc
Run all tests with Jest
Display a summary of test results

The npm test script is defined in package.json as "test": "tsc && jest"

Running Specific Tests

Jest provides powerful filtering options to run specific tests without executing the entire suite. Use the --testNamePattern (or -t) flag to target tests by name.

By Data Structure

Run all tests for a specific data structure:

npm test -- -t "Array"

By Algorithm

Run all tests for a specific algorithm:

npm test -- -t "Bubble sort"

By Problem Number

Run a specific coding problem:

npm test -- -t "Array Problem 1"

npm test -- -t "Tree Problem 3"

Problem tests are located in files with the .problems.test.ts suffix. Each problem includes multiple solution implementations with time and space complexity analysis.

Running Tests by File

You can also run tests from specific files:

npm test algorithms/sorting/quick-sort/quick-sort.test.ts

npm test data-structures/stack/stack.problems.test.ts

Test Output

Successful test runs will display:

PASS  data-structures/array/array.problems.test.ts
  Array
    Problem 1
      ✓ Solution 1 (3 ms)
      ✓ Solution 2 (in place) (1 ms)
    Problem 2
      ✓ Solution 1 (2 ms)

Test Suites: 1 passed, 1 total
Tests:       3 passed, 3 total
Snapshots:   0 total
Time:        1.234 s

Watch Mode

Run tests in watch mode to automatically re-run tests when files change:

npx jest --watch

In watch mode, you can press:

a - Run all tests
f - Run only failed tests
p - Filter by filename pattern
t - Filter by test name pattern
q - Quit watch mode

Test Coverage

Generate a test coverage report:

npx jest --coverage

This will display a coverage summary and create a detailed HTML report in the coverage/ directory.

Understanding Test Files

The project contains three types of test files:

Implementation Tests
Problem Tests
Design Technique Tests

Files ending in .test.ts contain unit tests for the data structure or algorithm implementation.

// stack.test.ts
describe("Stack", () => {
  it("should push items onto the stack", () => {
    const stack = new Stack();
    stack.push(1);
    expect(stack.size()).toBe(1);
  });
});

These tests verify that the implementation works correctly.

Files ending in .problems.test.ts contain solved coding problems.

// array.problems.test.ts
describe("Array", () => {
  describe("Problem 1", () => {
    /**
     * Time complexity: O(n²)
     * Space complexity: O(n²)
     */
    test("Solution 1", () => {
      // Problem solution implementation
    });
  });
});

These tests demonstrate practical applications and include complexity analysis.

Files in algorithms/design-techniques/ contain problems organized by algorithm design pattern.

// dynamic-programming.problems.test.ts
describe("Dynamic Programming", () => {
  test("Fibonacci sequence", () => {
    // DP solution
  });
});

These show how different techniques can be applied to solve problems.

Jest Configuration

The Jest configuration is defined in jest.config.js:

module.exports = {
  transform: {
    "^.+\\.(t|j)s$": ["@swc/jest"],
  },
};

This configuration uses SWC to transpile TypeScript and JavaScript files for faster test execution.

Advanced Jest Options

Run Tests in Parallel

Jest runs tests in parallel by default. To control the number of workers:

npm test -- --maxWorkers=4

Verbose Output

Display individual test results:

npm test -- --verbose

Clear Cache

If you encounter issues, clear Jest’s cache:

npx jest --clearCache

Update Snapshots

If using snapshot tests (not common in this project):

npm test -- -u

Debugging Tests

To debug tests in Node.js:

node --inspect-brk node_modules/.bin/jest --runInBand

Then open chrome://inspect in Chrome and click “inspect” on the Node process.

Use --runInBand to run tests serially (one at a time) which is helpful for debugging.

Continuous Integration

This project uses GitHub Actions for continuous integration. The CI pipeline runs all tests on every push and pull request to ensure code quality. You can view the CI status badge in the README:

Common Test Patterns

Testing Data Structures

Data structure tests typically verify:

Initialization and construction
Adding and removing elements
Searching and accessing elements
Edge cases (empty structure, single element, etc.)
Performance characteristics

Testing Algorithms

Algorithm tests typically verify:

Correct output for various inputs
Edge cases (empty arrays, single elements, etc.)
Sorted vs. unsorted inputs
Duplicate elements
Performance on large datasets

Testing Problem Solutions

Problem tests include:

Multiple solution approaches
Time and space complexity in comments
Expected output validation
Edge case handling

Next Steps

Data Structures

Explore the implemented data structures

Algorithms

Learn about sorting, searching, and graph algorithms

Get Started

Data Structures

Algorithms

Sorting Algorithms

Searching Algorithms

Graph Algorithms

Design Techniques

Test Framework

Running All Tests

Running Specific Tests

By Data Structure

By Algorithm

By Problem Number

Running Tests by File

Test Output

Watch Mode

Test Coverage

Understanding Test Files

Jest Configuration

Advanced Jest Options

Run Tests in Parallel

Verbose Output

Clear Cache

Update Snapshots

Debugging Tests

Continuous Integration

Common Test Patterns

Testing Data Structures

Testing Algorithms

Testing Problem Solutions

Next Steps

Data Structures

Algorithms

Build docs developers (and LLMs) love

Get Started

Data Structures

Algorithms

Sorting Algorithms

Searching Algorithms

Graph Algorithms

Design Techniques

​Test Framework

​Running All Tests

​Running Specific Tests

​By Data Structure

​By Algorithm

​By Problem Number

​Running Tests by File

​Test Output

​Watch Mode

​Test Coverage

​Understanding Test Files

​Jest Configuration

​Advanced Jest Options

​Run Tests in Parallel

​Verbose Output

​Clear Cache

​Update Snapshots

​Debugging Tests

​Continuous Integration

​Common Test Patterns

​Testing Data Structures

​Testing Algorithms

​Testing Problem Solutions

​Next Steps

Data Structures

Algorithms

Build docs developers (and LLMs) love

Test Framework

Running All Tests

Running Specific Tests

By Data Structure

By Algorithm

By Problem Number

Running Tests by File

Test Output

Watch Mode

Test Coverage

Understanding Test Files

Jest Configuration

Advanced Jest Options

Run Tests in Parallel

Verbose Output

Clear Cache

Update Snapshots

Debugging Tests

Continuous Integration

Common Test Patterns

Testing Data Structures

Testing Algorithms

Testing Problem Solutions

Next Steps