#192: Support multiple IdP signing certificates

[jskress]

This change updates service_provider.go to create an array of signing certificates from all those found in the IdP metadata. Issue #192 has details about why this is necessary.

Connected to #192

[jskress]

I don't know why the build failed. It was in duration_test.go, line 75. The offending case looks like line 55. The failure looks like a pointer comparison problem. Any thoughts?

[crewjam]

can you take a look at why the tests didn't pass please?

[jskress]

Looks like the error is on the Go tip only and has been there awhile. The Go 1.9 job passes.

[jskress]

I believe that this may have to do with changes Go made in errors and DeepEquals. If we change line 75 in duration_test.go, to read something like,

    if tc.err == nil {
        c.Assert(err, IsNil)
    } else {
        c.Assert(err.Error(), Equals, tc.err.Error())
    }

That should do the validation needed. Shall I add that to the PR?

[jskress]

Yep. That was it. Build passes now.