Add more GUI tests

**Description** Add GUI tests for the rest of the elements. I found a couple of bugs in `OperationsView`, so it seems like the tests are useful indeed.
**Testing** Tests pass
It is part of Scala's Predef
El 03/07/2014 22:21, "Sebastián Ortega" <notifications@github.com> escribió:

> In
> coinffeine-gui/src/test/scala/com/coinffeine/gui/setup/OkPayCredentialsStepPaneTest.scala:
>
> > +      val email = "email"
> > +      click("#email").`type`(email)
> > +      find[Node]("#testButton") should be ('disabled)
> > +      click("#email").eraseCharacters(email.length)
> > +      val password = "password"
> > +      click("#password").`type`(password)
> > +      find[Node]("#testButton") should be ('disabled)
> > +      click("#email").`type`(email)
> > +      click("#password").eraseCharacters(password.length)
> > +      find[Node]("#testButton") should be ('disabled)
> > +    }
> > +
> > +  it should behave like testValidationResult(
> > +    Future.successful(ValidCredentials), "valid credentials", "OK")
> > +
> > +  locally {
>
> What is this locally from?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/Coinffeine/coinffeine/pull/221/files#r14535934>.
>