Test responses older than max-age are not cached

package.json

@@ -34,6 +34,7 @@
   "devDependencies": {
     "ava": "^0.17.0",
     "coveralls": "^2.11.15",
+    "date-fns": "^1.21.1",
     "nock": "^9.0.2",
     "nyc": "^10.0.0",
     "snazzy": "^5.0.0"

test/cache.js

@@ -1,5 +1,6 @@
 import test from 'ava'
 import nock from 'nock'
+import subSeconds from 'date-fns/sub_seconds'
 import data from './fixtures/data'
 import Onionoo from '../'
 
@@ -55,3 +56,32 @@ test('Responses with future max-age are cached', async t => {
 
   t.deepEqual(cachedResponse.body, data.dummyResponse)
 })
+
+test('Responses older than max-age are not cached', async t => {
+  const onionoo = new Onionoo()
+
+  const defaultEndpoint = data.defaultEndpoints[0]
+  const responseHeaders = {
+    date: subSeconds(new Date(), 15).toUTCString(),
+    age: 0,
+    'cache-control': 'public, max-age=10'
+  }
+
+  const scope = nock(data.defaultBaseUrl)
+    .get(`/${defaultEndpoint}`)
+    .reply(200, data.dummyResponse, responseHeaders)
+
+  const response = await onionoo[defaultEndpoint]()
+
+  t.deepEqual(response.body, data.dummyResponse)
+  t.truthy(scope.isDone())
+
+  const scope2 = nock(data.defaultBaseUrl)
+    .get(`/${defaultEndpoint}`)
+    .reply(200, data.dummyResponse, responseHeaders)
+
+  const response2 = await onionoo[defaultEndpoint]()
+
+  t.deepEqual(response2.body, data.dummyResponse)
+  t.truthy(scope2.isDone())
+})