Use Duration scalar for recording lengths (#11)

src/types/recording.js

@@ -1,12 +1,11 @@
 import {
   GraphQLObjectType,
   GraphQLList,
-  GraphQLInt,
   GraphQLBoolean
 } from 'graphql/type'
 import Node from './node'
 import Entity from './entity'
-import { ISRC } from './scalars'
+import { Duration, ISRC } from './scalars'
 import {
   id,
   mbid,
@@ -51,7 +50,7 @@ or mixing.`,
 (ISRCs) for this recording.`
     },
     length: {
-      type: GraphQLInt,
+      type: Duration,
       description: `An approximation to the length of the recording, calculated
 from the lengths of the tracks using it.`
     },

test/fixtures/81a6d797dbe67ce75ba99ed2f5315ee0

@@ -0,0 +1 @@
+{"disambiguation":"","id":"9f9cf187-d6f9-437f-9d98-d59cdbd52757","video":false,"length":383493,"title":"Paranoid Android"}

test/fixtures/81a6d797dbe67ce75ba99ed2f5315ee0.headers

@@ -0,0 +1,27 @@
+{
+  "statusCode": 200,
+  "headers": {
+    "date": "Sun, 11 Dec 2016 22:49:10 GMT",
+    "content-type": "application/json; charset=utf-8",
+    "content-length": "122",
+    "connection": "keep-alive",
+    "keep-alive": "timeout=15",
+    "x-ratelimit-limit": "700",
+    "x-ratelimit-remaining": "535",
+    "x-ratelimit-reset": "1481496552",
+    "server": "Plack::Handler::Starlet",
+    "etag": "\"6a43a7029600ae595783f39d6d3d1f63\"",
+    "access-control-allow-origin": "*"
+  },
+  "url": "http://musicbrainz.org:80/ws/2/recording/9f9cf187-d6f9-437f-9d98-d59cdbd52757?fmt=json",
+  "time": 424,
+  "request": {
+    "method": "GET",
+    "headers": {
+      "User-Agent": "graphbrainz/4.2.0 ( https://github.com/exogen/graphbrainz )",
+      "host": "musicbrainz.org",
+      "accept-encoding": "gzip, deflate",
+      "accept": "application/json"
+    }
+  }
+}

test/schema.js

@@ -579,3 +579,16 @@ test('Works can be browsed by iswc', testData, `
     { title: 'Song of the French Partisan', iswcs: ['T-900.755.682-3'] }
   ])
 })
+
+test('Recordings have a length in milliseconds', testData, `
+  {
+    lookup {
+      recording(mbid: "9f9cf187-d6f9-437f-9d98-d59cdbd52757") {
+        length
+      }
+    }
+  }
+`, (t, data) => {
+  const { recording } = data.lookup
+  t.is(recording.length, 383493)
+})