ENH: Setting up esa, base template (#13)

Fixes #4

tests/helpers/responsive.js

@@ -0,0 +1,60 @@
+import Ember from 'ember';
+import MediaService from 'ember-responsive/media';
+
+const {
+  getOwner
+} = Ember;
+const { classify } = Ember.String;
+
+MediaService.reopen({
+  // Change this if you want a different default breakpoint in tests.
+  _defaultBreakpoint: 'desktop',
+
+  _breakpointArr: Ember.computed('breakpoints', function() {
+    return Object.keys(this.get('breakpoints')) || Ember.A([]);
+  }),
+
+  _forceSetBreakpoint(breakpoint) {
+    let found = false;
+
+    const props = {};
+    this.get('_breakpointArr').forEach(function(bp) {
+      const val = bp === breakpoint;
+      if (val) {
+        found = true;
+      }
+
+      props[`is${classify(bp)}`] = val;
+    });
+
+    if (found) {
+      this.setProperties(props);
+    } else {
+      throw new Error(
+        `You tried to set the breakpoint to ${breakpoint}, which is not in your app/breakpoint.js file.`
+      );
+    }
+  },
+
+  match() {}, // do not set up listeners in test
+
+  init() {
+    this._super(...arguments);
+
+    this._forceSetBreakpoint(this.get('_defaultBreakpoint'));
+  }
+});
+
+export default Ember.Test.registerAsyncHelper('setBreakpoint', function(app, breakpoint) {
+  // this should use getOwner once that's supported
+  const mediaService = app.__deprecatedInstance__.lookup('service:media');
+  mediaService._forceSetBreakpoint(breakpoint);
+});
+
+export function setBreakpointForIntegrationTest(container, breakpoint) {
+  const mediaService = getOwner(container).lookup('service:media');
+  mediaService._forceSetBreakpoint(breakpoint);
+  container.set('media', mediaService);
+
+  return mediaService;
+}