TestIAMMalformedEndpoint fails on Go 1.14 beta1

[eclipseo]

Fedora Rawhide witg Go 1.14 beta1:

Testing    in: /builddir/build/BUILD/minio-go-6.0.47/_build/src
         PATH: /builddir/build/BUILD/minio-go-6.0.47/_build/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/sbin
       GOPATH: /builddir/build/BUILD/minio-go-6.0.47/_build:/usr/share/gocode
  GO111MODULE: off
      command: go test -buildmode pie -compiler gc -ldflags "-X github.com/minio/minio-go/version=6.0.47 -extldflags '-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld '"
      testing: github.com/minio/minio-go
github.com/minio/minio-go/pkg/credentials
--- FAIL: TestIAMMalformedEndpoint (0.00s)
    iam_aws_test.go:139: Expected parse %%%%: invalid URL escape "%%%", got parse "%%%%": invalid URL escape "%%%"
FAIL
exit status 1
FAIL	github.com/minio/minio-go/pkg/credentials	0.014s

This is due to golang/go@64cfe9f and golang/go#29261

[vadmeste]

@eclipseo thanks for reporting this. I guess we can change a little bit the test to make it works with 1.14 and previous versions. Could you send a PR for that ?

[harshavardhana]

I think we should stop comparing error strings @vadmeste they are not meant to be compared, unless they are typed and we know exactly what to look for.

Probably we can look for url.EscapeError type but not look for the string, because those strings can change.

[vadmeste]

Yes, it looks like testing this way is enough:

       ee := url.EscapeError("")
       if !errors.As(err, &ee) {
               t.Fatalf("Expected invalid URL escape error, got %s", err)
       }