test: add comprehensive test coverage for getCacheAnalysis.ts (#79)

* Initial plan for issue

* Add comprehensive test coverage for getCacheAnalysis.ts

Co-authored-by: serhalp <[email protected]>

* Address PR feedback: fix NaN bug, refactor tests, export functions

Co-authored-by: serhalp <[email protected]>

* Extract functions to separate files and fix PR feedback

Co-authored-by: serhalp <[email protected]>

* Address PR feedback: fix test, remove package-lock.json, revert vitest config, extract getTimeToLive

Co-authored-by: serhalp <[email protected]>

* test: improve cache-control test coverage

---------

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: serhalp <[email protected]>
Co-authored-by: Philippe Serhal <[email protected]>

Author: Copilot

app/utils/cache-control.test.ts

@@ -0,0 +1,95 @@
+import { describe, it, expect } from 'vitest'
+
+import { parse, CacheControl } from './cache-control'
+
+describe('parse', () => {
+  it('parses max-age directive from cache control header', () => {
+    const result = parse('max-age=3600')
+
+    expect(result.maxAge).toBe(3600)
+  })
+
+  it('parses public directive from cache control header', () => {
+    expect(parse('public, max-age=5')).toHaveProperty('public', true)
+    expect(parse('max-age=5, public')).toHaveProperty('public', true)
+    expect(parse('max-age=5')).toHaveProperty('public', false)
+  })
+
+  it('parses s-maxage directive from cache control header', () => {
+    const result = parse('s-maxage=7200')
+
+    expect(result.sharedMaxAge).toBe(7200)
+  })
+
+  it('parses must-revalidate directive from cache control header', () => {
+    expect(parse('public, must-revalidate')).toHaveProperty('mustRevalidate', true)
+    expect(parse('must-revalidate, public')).toHaveProperty('mustRevalidate', true)
+    expect(parse('max-age=5, public')).toHaveProperty('mustRevalidate', false)
+  })
+
+  it('parses immutable directive from cache control header', () => {
+    expect(parse('public, immutable')).toHaveProperty('immutable', true)
+    expect(parse('immutable, public')).toHaveProperty('immutable', true)
+    expect(parse('max-age=5, public')).toHaveProperty('immutable', false)
+  })
+
+  it('parses private directive from cache control header', () => {
+    expect(parse('max-age=5, private')).toHaveProperty('private', true)
+    expect(parse('private, max-age=5')).toHaveProperty('private', true)
+    expect(parse('max-age=5, public')).toHaveProperty('private', false)
+  })
+
+  it('parses no-store directive from cache control header', () => {
+    expect(parse('max-age=5, no-store')).toHaveProperty('noStore', true)
+    expect(parse('no-store, max-age=5')).toHaveProperty('noStore', true)
+    expect(parse('max-age=5, public')).toHaveProperty('noStore', false)
+  })
+
+  it('parses no-cache directive from cache control header', () => {
+    expect(parse('max-age=5, no-cache')).toHaveProperty('noCache', true)
+    expect(parse('no-cache, max-age=5')).toHaveProperty('noCache', true)
+    expect(parse('max-age=5, public')).toHaveProperty('noCache', false)
+  })
+
+  it('returns null values when header is empty', () => {
+    const result = parse('')
+
+    expect(result.maxAge).toBe(null)
+    expect(result.public).toBe(null)
+  })
+
+  it('returns null values when header is null', () => {
+    const result = parse(null)
+
+    expect(result.maxAge).toBe(null)
+    expect(result.public).toBe(null)
+  })
+
+  it('returns null values when header is undefined', () => {
+    const result = parse(undefined)
+
+    expect(result.maxAge).toBe(null)
+    expect(result.public).toBe(null)
+  })
+
+  it('can be instantiated and used directly', () => {
+    const cc = new CacheControl()
+    const result = cc.parse('max-age=1800')
+
+    expect(result.maxAge).toBe(1800)
+  })
+
+  it('parses extension directives without values', () => {
+    const result = parse('max-age=3600, durable')
+
+    expect(result.maxAge).toBe(3600)
+    expect(result.extensions).toHaveProperty('durable', null)
+  })
+
+  it('parses extension directives with values', () => {
+    const result = parse('max-age=3600, fishiness=42')
+
+    expect(result.maxAge).toBe(3600)
+    expect(result.extensions).toHaveProperty('fishiness', '42')
+  })
+})

app/utils/getCacheAnalysis.test.ts

@@ -1,93 +1,165 @@
 import { describe, it, expect } from 'vitest'
 
-import { getTimeToLive } from './getCacheAnalysis'
+import getCacheAnalysis, { parseCacheStatus } from './getCacheAnalysis'
+import { ServedBySource } from './getServedBy'
 
 describe('getCacheAnalysis', () => {
-  it.todo('works')
-})
+  it('returns cache analysis structure with basic CDN headers', () => {
+    const headers = {
+      'Cache-Status': '"Netlify Edge"; hit',
+      'Debug-X-BB-Host-Id': 'node1.example.com',
+    }
+    const now = Date.now()
+
+    const result = getCacheAnalysis(headers, now)
+
+    expect(result).toHaveProperty('servedBy')
+    expect(result).toHaveProperty('cacheStatus')
+    expect(result).toHaveProperty('cacheControl')
+    expect(result.servedBy.source).toBe(ServedBySource.CDN)
+  })
 
-describe('getTimeToLive', () => {
-  it('returns the diff in seconds from `maxAge` to `age` if they are both defined', () => {
-    const age = 10
-    const date = undefined
-    const expiresAt = undefined
-    const maxAge = 25
+  it('integrates Cache-Status parsing correctly', () => {
+    const headers = {
+      'Cache-Status': '"Next.js"; hit, "Netlify Edge"; hit',
+      'Debug-X-BB-Host-Id': 'node1.example.com',
+    }
     const now = Date.now()
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
+    const result = getCacheAnalysis(headers, now)
+
+    expect(result.cacheStatus).toHaveLength(2)
+    expect(result.cacheStatus[0]?.cacheName).toBe('Netlify Edge')
+    expect(result.cacheStatus[1]?.cacheName).toBe('Next.js')
   })
 
-  it('returns the diff in seconds from `maxAge` to `age` if they are both defined as well as `date`', () => {
-    const age = 10
-    const date = new Date(999_999_999)
-    const expiresAt = undefined
-    const maxAge = 25
+  it('integrates cache control parsing correctly', () => {
+    const headers = {
+      'Cache-Control': 'max-age=3600',
+      'Cache-Status': '"Netlify Edge"; hit',
+      'Debug-X-BB-Host-Id': 'node1.example.com',
+    }
     const now = Date.now()
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
+    const result = getCacheAnalysis(headers, now)
+
+    expect(result.cacheControl.isCacheable).toBe(true)
+    expect(typeof result.cacheControl.ttl).toBe('number')
   })
 
-  it('returns the diff in seconds from `maxAge` to `now - date` if `maxAge` and `date` are defined but not `age`', () => {
-    const age = undefined
-    const date = new Date(1_000_000)
-    const expiresAt = undefined
-    const maxAge = 25
-    const now = new Date(1_000_000 + 10_000).getTime()
+  it('integrates served by determination correctly', () => {
+    const headers = {
+      'Cache-Status': '"Netlify Durable"; hit',
+      'Debug-X-BB-Host-Id': 'node1.example.com',
+    }
+    const now = Date.now()
+
+    const result = getCacheAnalysis(headers, now)
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
+    expect(result.servedBy.source).toBe(ServedBySource.DurableCache)
+    expect(result.servedBy.cdnNodes).toBe('node1.example.com')
   })
 
-  it('returns the diff in seconds from `maxAge` to `now` if `maxAge` is defined but neither `age` nor `date`', () => {
-    const age = undefined
-    const date = undefined
-    const expiresAt = undefined
-    const maxAge = 25
-    const now = new Date(1_000_000 + 10_000).getTime()
+  it('handles empty headers gracefully', () => {
+    const headers = {}
+    const now = Date.now()
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(25)
+    expect(() => getCacheAnalysis(headers, now)).toThrow('Could not determine who served the request')
   })
+})
+
+describe('parseCacheStatus', () => {
+  it('parses single cache status entry with hit parameter', () => {
+    const cacheStatus = '"Netlify Edge"; hit'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result).toEqual([
+      {
+        cacheName: 'Netlify Edge',
+        parameters: {
+          'hit': true,
+          'fwd': undefined,
+          'fwd-status': undefined,
+          'ttl': undefined,
+          'stored': false,
+          'collapsed': false,
+          'key': undefined,
+          'detail': undefined,
+        },
+      },
+    ])
+  })
+
+  it('parses multiple cache status entries with different parameters', () => {
+    const cacheStatus = '"Next.js"; hit, "Netlify Durable"; fwd=miss; stored, "Netlify Edge"; fwd=miss'
 
-  it('returns the diff in seconds from `expiresAt` to `now - age` if `maxAge` and `date` are not defined and `expiresAt` and `age` are defined', () => {
-    const age = 10
-    const date = undefined
-    const expiresAt = new Date(1_000_000 + 25_000)
-    const maxAge = null
-    const now = new Date(1_000_000 + 10_000).getTime()
+    const result = parseCacheStatus(cacheStatus)
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
+    expect(result).toHaveLength(3)
+    expect(result[0]?.cacheName).toBe('Netlify Edge') // Should be reversed per spec
+    expect(result[1]?.cacheName).toBe('Netlify Durable')
+    expect(result[2]?.cacheName).toBe('Next.js')
+    expect(result[0]?.parameters.fwd).toBe('miss')
+    expect(result[1]?.parameters.stored).toBe(true)
+    expect(result[2]?.parameters.hit).toBe(true)
   })
 
-  // FIXME(serhalp) Real bug. Fix logic. It's depending on `now` when given two absolute dates...
-  it.fails(
-    'returns the diff in seconds from `expiresAt` to `date` if `maxAge` and `age` are not defined and `expiresAt` and `date` are defined',
-    () => {
-      const age = undefined
-      const date = new Date(1_000_000)
-      const expiresAt = new Date(1_000_000 + 15_000)
-      const maxAge = null
-      const now = Date.now()
-
-      expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
-    },
-  )
-
-  it('returns the diff in seconds from `expiresAt` to `now` if `maxAge`, `age`, and `date` are not defined and `expiresAt` is defined', () => {
-    const age = undefined
-    const date = undefined
-    const expiresAt = new Date(1_000_000 + 15_000)
-    const maxAge = null
-    const now = new Date(1_000_000).getTime()
-
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBe(15)
+  it('parses cache status with numeric parameters', () => {
+    const cacheStatus = '"Netlify Edge"; hit; fwd-status=200; ttl=3600'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result[0]?.parameters['fwd-status']).toBe(200)
+    expect(result[0]?.parameters.ttl).toBe(3600)
   })
 
-  it('returns `undefined` if `maxAge` and `expiresAt` are not defined', () => {
-    const age = 10
-    const date = new Date()
-    const expiresAt = undefined
-    const maxAge = null
-    const now = Date.now()
+  it('parses cache status with string parameters', () => {
+    const cacheStatus = '"Netlify Edge"; hit; key=cache-key-123; detail=some-detail'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result[0]?.parameters.key).toBe('cache-key-123')
+    expect(result[0]?.parameters.detail).toBe('some-detail')
+  })
+
+  it('handles empty cache status string', () => {
+    const result = parseCacheStatus('')
+
+    expect(result).toEqual([])
+  })
+
+  it('ignores invalid cache status entries without parameters', () => {
+    const cacheStatus = '"Netlify Edge", "Valid Cache"; hit'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result).toHaveLength(1)
+    expect(result[0]?.cacheName).toBe('Valid Cache')
+  })
+
+  it('ignores cache status entries with invalid parameters', () => {
+    const cacheStatus = '"Netlify Edge"; ; hit'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result).toHaveLength(1)
+    expect(result[0]?.cacheName).toBe('Netlify Edge')
+    expect(result[0]?.parameters.hit).toBe(true)
+  })
+
+  it('sorts cache entries according to RFC 9211 precedence', () => {
+    const cacheStatus = '"Netlify Edge"; hit, "Next.js"; hit, "Netlify Durable"; hit'
+
+    const result = parseCacheStatus(cacheStatus)
+
+    expect(result[0]?.cacheName).toBe('Netlify Edge')
+    expect(result[1]?.cacheName).toBe('Netlify Durable')
+    expect(result[2]?.cacheName).toBe('Next.js')
+  })
 
-    expect(getTimeToLive(age, date, expiresAt, maxAge, now)).toBeUndefined()
+  it('parses forward parameter values from cache status entries', () => {
+    const result = parseCacheStatus('"Cache"; fwd=bypass')
+    expect(result[0]?.parameters.fwd).toBe('bypass')
   })
 })