Add some tests for computed properties on submit controller.
Add some tests for computed properties on submit controller.

CenterForOpenScience/ember-preprints,baylee-d/ember-preprints,baylee-d/ember-preprints,laurenrevere/ember-preprints,laurenrevere/ember-preprints,CenterForOpenScience/ember-preprints,caneruguz/ember-preprints,caneruguz/ember-preprints