hack/testdata/dockerconfig.json

{
    "auths":{
        "http://foo.example.com":{
            "username":"foo",
            "password":"bar",
            "email":"foo@example.com"
        },
        "http://bar.example.com":{
            "username":"bar",
            "password":"baz",
            "email":"bar@example.com"
        }
    }
}