Make button text A/B testable - Sitecore MVC - asp.net-mvc-4

Question

I have an MVC/angularJS page with a button, the button needs to call code to process the current page and proceed to the next step in the application, but they want the button text to be a/b testable with different variations. I'm new to Sitecore so am struggling to know the best way of doing things.
I thought of having a simple text component/template which just has a single line text property, but if I add that to the page template then it doesn't seem a/b testable because when you click on the test option it asks you to select content. Whereas the content was text they entered as part of the page template.
The only way I know of making a/b testable content so that they can click on the page in page editor and choose to select content / add test variation. I wouldn't add the button to the placeholder as it needs to call specific angular code and always be there, but should I be adding a placeholder where the text is? It seems like overkill to have to define a placeholder there, define a rendering, create a partial view, define placeholder settings to limit it to the simple text component, and then hope they don't try adding multiple items to the placeholder.

Answer 1

I would make a separate template (ie with the text field for your button) to represent your form, then either create the two test variation items as children of your page, or maybe place them in a shared components folder outside of your 'home' node.
EDIT
In order to move your form component into a new A/B testable component you would need to create a new Sublayout in Sitecore, then create a new ascx control for the sublayout. In the Page_Load handler of this control, you would use the following code to retrieve the datasource of the sublayout:
//assume you have a button on your usercontrol called btnSubmit
//assume your template has a single-line text field called 'SubmitButtonText'
Guid dataSourceId;
Sitecore.Data.Items.Item dataSource;
if (Guid.TryParse(sublayout.DataSource, out dataSourceId))
{
dataSource = Sitecore.Context.Database.GetItem(new ID(dataSourceId));
btnSubmit.Text = dataSource["SubmitButtonText"];
}

Answer 2

So I created a new template which just had a single line of text as a field, and added a content item in a shared data node.
In my partial view:
#model Digital.Models.SimpleTextItem
<button ....>
<span class="hidden-xs">#Model.SimpleText_Value<br></span>
</button>
In my main page - I was trying to statically bind it so that they could only change content rather than add new controls to the placeholder, but that only worked if I specified the datasource in this page.
Using a rendering, and in the page layout adding the rendering to the placeholder with a specified data source:
#Html.Sitecore().Placeholder("PremiumQuoteApplyNowPlaceHolder")
Not sure if it was the best approach but it achieves what I need it to.

Answer 3

A/B testing could be applied only to controls(XSLT renderings, sublayouts, action controller renderings, view renderings). If you want to make A/B testing only for button then you should create additional control for it as you did.
Technical details for MVC: A/B testing is applied on mvc.customizeRendering pipeline where rendering arguments are processed. This pipeline operates on renderings level. It means that you are not able to create A/B testing for particular field(button) without your own customization.