[META] add tests

[jenlampton]

Here's a list of test to write:

Entity API:

• Test each core entity has a label and status field defined

Admin UI:

• create reference field
• select entity type on the settings form
• check autocomplete widget exists
• create reference field on a non-node entity
• entity type without a label can't be referenced and returns message
• bundle text uses bundle label where available
• bundle label defaults to 'type'
• bundle option removed for entities without bundles
• Ensure that the entity type's bundle key matches a column in its base table.
• status checkbox disabled on instance settings for entity type that doesn't define status key
• entity type select disabled after field has data
• change to bundle and status are reset after entity type changes

Autocomplete:

• autocomplete callback reads field settings properly
• autocomplete respects bundle
• autocomplete respects status
• feeding a bad id number
• respects permissions
• works on entities without status

Content edit UI:

• changing an existing field value
• display value on entity view
• required field cannot be blank
• default value entered in the instance form

Output:

• Link to entity displayed.
• Nodes can be rendered properly.
• Comments can be rendered properly.

Views:

• Reference field can be displayed in view
• Relationship can be set up on Reference view

Layouts:

• Relationship can be set up on layout context

[jenlampton]

As we talked about today at BackdropLIVE, @hosef plans to steal the tests from the D7 contrib modules, and adapt those as necessary.