Testing And Benchmarking in TypeScript

Here’s an idiomatic TypeScript example demonstrating unit testing and benchmarking:

// math.ts
export function intMin(a: number, b: number): number {
  return a < b ? a : b;
}

// math.test.ts
import { intMin } from './math';

describe('intMin', () => {
  it('should return the minimum of two integers', () => {
    expect(intMin(2, -2)).toBe(-2);
  });

  it.each([
    [0, 1, 0],
    [1, 0, 0],
    [2, -2, -2],
    [0, -1, -1],
    [-1, 0, -1],
  ])('should return %i for intMin(%i, %i)', (a, b, expected) => {
    expect(intMin(a, b)).toBe(expected);
  });
});

// math.bench.ts
import { intMin } from './math';
import { performance } from 'perf_hooks';

function benchmarkIntMin(iterations: number): number {
  const start = performance.now();
  for (let i = 0; i < iterations; i++) {
    intMin(1, 2);
  }
  const end = performance.now();
  return end - start;
}

console.log(`Benchmark: ${benchmarkIntMin(1000000)} ms`);

This example demonstrates unit testing and benchmarking in TypeScript. Let’s break it down:

1. We define a simple intMin function in math.ts that returns the minimum of two numbers.

2. In math.test.ts, we use Jest (a popular testing framework for TypeScript) to write unit tests:

   • The first test checks a basic case.
   • The second test uses it.each to run multiple test cases in a table-driven style.

3. In math.bench.ts, we create a simple benchmark function that measures the time taken to run intMin a specified number of times.

To run the tests and benchmark:

1. Install the necessary dependencies:

   npm install --save-dev typescript ts-jest @types/jest

2. Configure Jest in your package.json:

   {
     "jest": {
       "preset": "ts-jest",
       "testEnvironment": "node"
     }
   }

3. Run the tests:

   npx jest

4. Run the benchmark:

   ts-node math.bench.ts

This example showcases TypeScript’s strong typing (e.g., function parameters and return types) and uses modern testing practices like table-driven tests. The benchmark demonstrates how to measure performance, although for more complex scenarios, you might want to use a dedicated benchmarking library.

Remember that TypeScript is transpiled to JavaScript, so you don’t compile it directly to a binary like in Go. Instead, you typically run it through Node.js or bundle it for browser use.