spec: Add test case for fetch

spec/chromium-spec.js

@@ -496,4 +496,25 @@ describe('chromium feature', function () {
       })
     })
   })
+
+  describe('fetch', function () {
+    it('does not crash', function (done) {
+      const server = http.createServer(function (req, res) {
+        res.end('test')
+        server.close()
+      })
+      server.listen(0, '127.0.0.1', function () {
+        const port = server.address().port
+        fetch(`http://127.0.0.1:${port}`).then((res) => {
+          return res.body.getReader()
+        }).then((reader) => {
+          reader.read().then((r) => {
+            reader.cancel()
+          })
+        }).catch(function (e) {
+          done()
+        })
+      })
+    })
+  })
 })