Discovery Service should be covered with unit tests

[peppelinux]

We merged this #233 and fixed the indentation errors, unit tests now works fine but we should have a valid test for this feature.

@vgiralt that would be for you if you agree

[vgiralt]

I agree, but I might need some guidance, as unit testing is my "pending subject"

[peppelinux]

Just try to see how the tests was made and put a configuration with a unknow idp that should be handled with DS.

1. A call that must produce a redirect to DS url
2. Another call that should put in the GET args the DS returning values to handle in the view.

Keep also in mind that today we moved to
#235

[peppelinux]

Done here:
86a5dc7