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Testing HTTP Redirect Back Functionality in Koa.js

This test suite validates the back() functionality in Koa’s response handling, focusing on HTTP redirection behavior. The tests verify different scenarios for the ctx.back() method, including referrer-based redirects and fallback paths.

Test Coverage Overview

The test suite provides comprehensive coverage of the ctx.back() method’s redirection logic.

Tests referrer header-based redirects
Validates referer header alternative spelling
Verifies fallback to provided alternative path
Confirms default root path redirection

Implementation Analysis

The testing approach uses Node’s built-in test framework with a modular structure. The implementation leverages context helpers for test setup and employs assertion-based verification patterns.

Uses describe/it blocks for test organization
Implements isolated context creation per test
Utilizes header manipulation for testing scenarios

Technical Details

Node.js test runner (node:test)
Assert module for validations
Custom context test helpers
HTTP header simulation
Location header verification

Best Practices Demonstrated

The test suite exemplifies clean testing practices with isolated test cases and clear assertions. Each test focuses on a specific aspect of the back() functionality, maintaining single responsibility principle.

Independent test contexts
Clear test case descriptions
Consistent assertion patterns
Comprehensive edge case coverage

koajs/koa

__tests__/response/back.test.js

            
'use strict'

const { describe, it } = require('node:test')
const assert = require('assert')
const context = require('../../test-helpers/context')

describe('ctx.back([alt])', () => {
  it('should redirect to Referrer', () => {
    const ctx = context()
    ctx.req.headers.referrer = '/login'
    ctx.back()
    assert.equal(ctx.response.header.location, '/login')
  })

  it('should redirect to Referer', () => {
    const ctx = context()
    ctx.req.headers.referer = '/login'
    ctx.back()
    assert.equal(ctx.response.header.location, '/login')
  })

  it('should default to alt', () => {
    const ctx = context()
    ctx.back('/index.html')
    assert.equal(ctx.response.header.location, '/index.html')
  })

  it('should default redirect to /', () => {
    const ctx = context()
    ctx.back()
    assert.equal(ctx.response.header.location, '/')
  })
})