Set environment to return mocked GraphQL operations

todo/data/fixture.js

@@ -0,0 +1,24 @@
+export const fixture = {
+  "appQuery": {
+    "todos": {
+      "edges": [
+        {
+          "node": {
+            "id": "VG9kbzow",
+            "__typename": "Todo",
+            "text": "This's a fixture"
+          },
+          "cursor": "YXJyYXljb25uZWN0aW9uOjA="
+        },
+        {
+          "node": {
+            "id": "VG9kbzox",
+            "__typename": "Todo",
+            "text": "Created with easygraphql-tester"
+          },
+          "cursor": "YXJyYXljb25uZWN0aW9uOjE="
+        }
+      ]
+    }
+  }
+}

todo/js/app.js

@@ -14,13 +14,30 @@ import 'todomvc-common';
 
 import React from 'react';
 import ReactDOM from 'react-dom';
+import EasyGraphQLTester from 'easygraphql-tester';
+import { schema } from '../data/schema';
+import { fixture } from '../data/fixture';
 
 import {QueryRenderer, graphql} from 'react-relay';
 import {Environment, Network, RecordSource, Store} from 'relay-runtime';
 
 import TodoApp from './components/TodoApp';
 
+const tester = new EasyGraphQLTester(schema);
+
 function fetchQuery(operation, variables) {
+  if (process.env.NODE_ENV === 'none') {
+    const mockedQuery = tester.mock({
+      query: operation.text,
+      variables,
+      fixture: fixture[operation.name]
+    })
+    const response = {
+      "data": mockedQuery
+    }
+    return response
+  }
+
   return fetch('/graphql', {
     method: 'POST',
     headers: {