Add submitForm action

To get the submitHandler called, we add a submitForm action on the component, so that it will be called when the form is submitted. Then we retrieve the "submitHandler" property of the component, and call it as a function.

Inner green; outer red: TypeError: this.submitHandler is not a function

Now our component test is able to verify that the submit handler is called. Now the acceptance test errors out because submitting the form expects a submitHandler to be passed in, and there isn't one.

app/components/post-form.js

@@ -1,4 +1,9 @@
 import Component from '@ember/component';
 
 export default Component.extend({
+  actions: {
+    submitForm() {
+      this.submitHandler();
+    }
+  }
 });

app/templates/components/post-form.hbs

@@ -8,5 +8,5 @@
     <textarea class="js-post-form-body" />
   </div>
 
-  <button type="button" class="js-post-form-save">Save</button>
+  <button type="button" class="js-post-form-save" onclick={{action "submitForm"}}>Save</button>
 </form>