Simulate error cases 50% of the time to have a great demo

Author: Matthieu Napoli

App/Containers/HomeScreen.js

@@ -1,5 +1,5 @@
 import React from 'react'
-import { Platform, StyleSheet, Text, View } from 'react-native'
+import { Platform, StyleSheet, Text, View, Button } from 'react-native'
 import { connect } from 'react-redux'
 import { PropTypes } from 'prop-types'
 import ExampleActions from 'App/Stores/Example/Actions'
@@ -24,6 +24,7 @@ class HomeScreen extends React.Component {
           The weather temperature is: {this.props.temperature}
         </Text>
         <Text style={styles.instructions}>{this.props.errorMessage}</Text>
+        <Button onPress={this.props.fetchTemperature} title="Refresh"/>
       </View>
     )
   }

App/Service/WeatherService.js

@@ -10,6 +10,13 @@ const weatherApiClient = create({
 })
 
 function fetchTemperature() {
+  // Simulate an error 50% of the time just for testing purposes
+  if (Math.random() > 0.5) {
+    return new Promise(function(resolve, reject) {
+      resolve(null);
+    });
+  }
+
   const locationQuery = escape(
     "select item.condition.temp from weather.forecast where woeid in (select woeid from geo.places where text='Lyon, Rhone-Alpes, FR') and u='c'"
   )