unit-test-generator

Generate comprehensive unit tests with edge cases and AAA pattern.

Safety Notice

This listing is imported from skills.sh public index metadata. Review upstream SKILL.md and repository scripts before running.

Copy this and send it to your AI assistant to learn

Install skill "unit-test-generator" with this command: npx skills add monkey1sai/openai-cli/monkey1sai-openai-cli-unit-test-generator

Unit Test Generator

Generate comprehensive unit tests with edge cases and AAA pattern.

AAA Pattern Template

// tests/utils/validator.test.ts import { describe, it, expect } from "vitest"; import { validateEmail } from "@/utils/validator";

describe("validateEmail", () => { it("should return true for valid email", () => { // Arrange const email = "user@example.com";

// Act
const result = validateEmail(email);

// Assert
expect(result).toBe(true);

});

it("should return false for invalid email - missing @", () => { // Arrange const email = "userexample.com";

// Act
const result = validateEmail(email);

// Assert
expect(result).toBe(false);

});

it("should return false for invalid email - missing domain", () => { // Arrange const email = "user@";

// Act
const result = validateEmail(email);

// Assert
expect(result).toBe(false);

}); });

Comprehensive Test Cases

// src/utils/calculator.ts export function divide(a: number, b: number): number { if (b === 0) { throw new Error("Division by zero"); } return a / b; }

// tests/utils/calculator.test.ts describe("divide", () => { describe("happy path", () => { it("should divide positive numbers", () => { expect(divide(10, 2)).toBe(5); });

it("should divide negative numbers", () => {
  expect(divide(-10, 2)).toBe(-5);
  expect(divide(10, -2)).toBe(-5);
  expect(divide(-10, -2)).toBe(5);
});

it("should handle decimal results", () => {
  expect(divide(10, 3)).toBeCloseTo(3.333, 3);
});

});

describe("edge cases", () => { it("should handle zero dividend", () => { expect(divide(0, 5)).toBe(0); });

it("should handle very large numbers", () => {
  expect(divide(Number.MAX_SAFE_INTEGER, 2)).toBe(
    Number.MAX_SAFE_INTEGER / 2
  );
});

it("should handle very small numbers", () => {
  expect(divide(0.0001, 0.0001)).toBe(1);
});

});

describe("error cases", () => { it("should throw error when dividing by zero", () => { expect(() => divide(10, 0)).toThrow("Division by zero"); });

it("should throw error when dividing by negative zero", () => {
  expect(() => divide(10, -0)).toThrow("Division by zero");
});

}); });

Async Function Testing

// src/services/userService.ts export async function fetchUser(id: string): Promise<User> { const response = await fetch(/api/users/${id});

if (!response.ok) { throw new Error(User not found: ${id}); }

return response.json(); }

// tests/services/userService.test.ts describe("fetchUser", () => { beforeEach(() => { global.fetch = vi.fn(); });

afterEach(() => { vi.resetAllMocks(); });

it("should fetch user successfully", async () => { // Arrange const mockUser = { id: "123", name: "John" }; (global.fetch as any).mockResolvedValueOnce({ ok: true, json: async () => mockUser, });

// Act
const user = await fetchUser("123");

// Assert
expect(user).toEqual(mockUser);
expect(global.fetch).toHaveBeenCalledWith("/api/users/123");

});

it("should throw error when user not found", async () => { // Arrange (global.fetch as any).mockResolvedValueOnce({ ok: false, });

// Act &#x26; Assert
await expect(fetchUser("999")).rejects.toThrow("User not found: 999");

});

it("should handle network error", async () => { // Arrange (global.fetch as any).mockRejectedValueOnce(new Error("Network error"));

// Act &#x26; Assert
await expect(fetchUser("123")).rejects.toThrow("Network error");

}); });

Testing Classes

// src/models/ShoppingCart.ts export class ShoppingCart { private items: CartItem[] = [];

add(item: CartItem): void { this.items.push(item); }

remove(itemId: string): void { this.items = this.items.filter((i) => i.id !== itemId); }

getTotal(): number { return this.items.reduce( (sum, item) => sum + item.price * item.quantity, 0 ); }

clear(): void { this.items = []; } }

// tests/models/ShoppingCart.test.ts describe("ShoppingCart", () => { let cart: ShoppingCart;

beforeEach(() => { cart = new ShoppingCart(); });

describe("add", () => { it("should add item to cart", () => { // Arrange const item = { id: "1", name: "Product", price: 10, quantity: 1 };

  // Act
  cart.add(item);

  // Assert
  expect(cart.getTotal()).toBe(10);
});

it("should add multiple items", () => {
  // Arrange
  const item1 = { id: "1", name: "Product 1", price: 10, quantity: 1 };
  const item2 = { id: "2", name: "Product 2", price: 20, quantity: 2 };

  // Act
  cart.add(item1);
  cart.add(item2);

  // Assert
  expect(cart.getTotal()).toBe(50); // 10 + (20 * 2)
});

});

describe("remove", () => { it("should remove item from cart", () => { // Arrange const item = { id: "1", name: "Product", price: 10, quantity: 1 }; cart.add(item);

  // Act
  cart.remove("1");

  // Assert
  expect(cart.getTotal()).toBe(0);
});

it("should not throw when removing non-existent item", () => {
  // Act &#x26; Assert
  expect(() => cart.remove("999")).not.toThrow();
});

});

describe("getTotal", () => { it("should return 0 for empty cart", () => { expect(cart.getTotal()).toBe(0); });

it("should calculate total with quantities", () => {
  // Arrange
  cart.add({ id: "1", name: "Product", price: 10, quantity: 3 });

  // Assert
  expect(cart.getTotal()).toBe(30);
});

});

describe("clear", () => { it("should remove all items", () => { // Arrange cart.add({ id: "1", name: "Product 1", price: 10, quantity: 1 }); cart.add({ id: "2", name: "Product 2", price: 20, quantity: 1 });

  // Act
  cart.clear();

  // Assert
  expect(cart.getTotal()).toBe(0);
});

}); });

Testing React Components

// src/components/Counter.tsx export function Counter() { const [count, setCount] = useState(0);

return ( <div> <p>Count: {count}</p> <button onClick={() => setCount(count + 1)}>Increment</button> <button onClick={() => setCount(0)}>Reset</button> </div> ); }

// tests/components/Counter.test.tsx import { render, screen, fireEvent } from "@testing-library/react";

describe("Counter", () => { it("should render with initial count of 0", () => { // Arrange & Act render(<Counter />);

// Assert
expect(screen.getByText("Count: 0")).toBeInTheDocument();

});

it("should increment count when button clicked", () => { // Arrange render(<Counter />); const button = screen.getByText("Increment");

// Act
fireEvent.click(button);

// Assert
expect(screen.getByText("Count: 1")).toBeInTheDocument();

});

it("should increment multiple times", () => { // Arrange render(<Counter />); const button = screen.getByText("Increment");

// Act
fireEvent.click(button);
fireEvent.click(button);
fireEvent.click(button);

// Assert
expect(screen.getByText("Count: 3")).toBeInTheDocument();

});

it("should reset count to 0", () => { // Arrange render(<Counter />); fireEvent.click(screen.getByText("Increment"));

// Act
fireEvent.click(screen.getByText("Reset"));

// Assert
expect(screen.getByText("Count: 0")).toBeInTheDocument();

}); });

Edge Case Categories

// Test case generation template interface TestCase { category: "happy-path" | "edge-case" | "error-case"; description: string; input: any; expectedOutput: any; }

const testCases: TestCase[] = [ // Happy path { category: "happy-path", description: "typical valid input", input: "user@example.com", expectedOutput: true, },

// Edge cases { category: "edge-case", description: "empty string", input: "", expectedOutput: false, }, { category: "edge-case", description: "null input", input: null, expectedOutput: false, }, { category: "edge-case", description: "undefined input", input: undefined, expectedOutput: false, }, { category: "edge-case", description: "whitespace only", input: " ", expectedOutput: false, }, { category: "edge-case", description: "very long email", input: "a".repeat(1000) + "@example.com", expectedOutput: false, },

// Error cases { category: "error-case", description: "invalid format - no @", input: "userexample.com", expectedOutput: false, }, { category: "error-case", description: "invalid format - multiple @", input: "user@@example.com", expectedOutput: false, }, ];

Coverage Notes

/**

  • Coverage targets for this module:
    • Line coverage: 100% (all lines executed)
    • Branch coverage: 100% (all if/else paths tested)
    • Function coverage: 100% (all functions called)
    • Statement coverage: 100% (all statements executed)
  • Untested scenarios (intentionally):
    • None - module is fully covered
  • High-risk areas requiring extra attention:
    • Division by zero handling
    • Null/undefined input handling
    • Type coercion edge cases */

Test File Structure

src/ utils/ validator.ts calculator.ts services/ userService.ts models/ ShoppingCart.ts components/ Counter.tsx

tests/ utils/ validator.test.ts calculator.test.ts services/ userService.test.ts models/ ShoppingCart.test.ts components/ Counter.test.tsx

Test Generation Script

// scripts/generate-tests.ts import * as fs from "fs"; import * as path from "path";

function generateTestTemplate(filePath: string): string { const fileName = path.basename(filePath, path.extname(filePath)); const className = fileName.charAt(0).toUpperCase() + fileName.slice(1);

return ` import { describe, it, expect } from 'vitest'; import { ${className} } from '@/${filePath}';

describe('${className}', () => { describe('happy path', () => { it('should handle typical case', () => { // Arrange const input = /* TODO */;

  // Act
  const result = ${className}(input);

  // Assert
  expect(result).toBe(/* TODO */);
});

});

describe('edge cases', () => { it('should handle null input', () => { // Arrange const input = null;

  // Act &#x26; Assert
  expect(() => ${className}(input)).toThrow();
});

it('should handle empty input', () => {
  // Arrange
  const input = '';

  // Act
  const result = ${className}(input);

  // Assert
  expect(result).toBe(/* TODO */);
});

});

describe('error cases', () => { it('should throw error for invalid input', () => { // Arrange const input = /* TODO */;

  // Act &#x26; Assert
  expect(() => ${className}(input)).toThrow('Invalid input');
});

}); }); `.trim(); }

Best Practices

  • AAA pattern: Arrange-Act-Assert structure

  • One assertion per test: Keep tests focused

  • Descriptive names: "should [expected behavior] when [condition]"

  • Test edge cases: null, undefined, empty, max values

  • Test errors: Verify error handling

  • Isolated tests: No shared state between tests

  • Fast tests: Unit tests should run in milliseconds

Output Checklist

  • Test file created matching source structure

  • AAA pattern used consistently

  • Happy path cases covered

  • Edge cases identified and tested

  • Error cases tested

  • Async functions tested with proper awaits

  • Mocks used for dependencies

  • Coverage notes documented

  • Descriptive test names

  • Setup/teardown hooks used appropriately

Source Transparency

This detail page is rendered from real SKILL.md content. Trust labels are metadata-based hints, not a safety guarantee.

Open in GitHubOpen in ClawHub

Related Skills

Related by shared tags or category signals.

Coding

eslint-prettier-config

No summary provided by upstream source.

Repository SourceNeeds Review
-9
monkey1sai
Coding

api-docs-generator

No summary provided by upstream source.

Repository SourceNeeds Review
-9
monkey1sai
Coding

rate-limiting-abuse-protection

No summary provided by upstream source.

Repository SourceNeeds Review
-9
monkey1sai