Test for trialing slashes in value for 'issuer' from '/.well-known/openid-configuration' responses

Basically our ESS Brokers are advertising themselves (in their /.well-known/openid-configuration responses) as issuers with a trailing slash, e.g. for https://broker.pod.inrupt.com/.well-known/openid-configuration:

{
    "introspection_endpoint": "https://broker.pod.inrupt.com/introspect",
    "scopes_supported": [
        "openid",
        "offline_access",
        "webid"
    ],
    "issuer": "https://broker.pod.inrupt.com/",
    :

Note the trailing slash on the issuer URL (which is technically (slightly!) more correct than having the URL without the trailing slash).
So it seems NSS might be blindly taking that issuer value, and appending the string literal /.well-known/openid-configuration to it, without first checking if the issuer value has a trailing slash or not. If the URL constructed has two slashes, then the server responds with it’s standard HTML ‘Page Not Found’ response, which results in the ‘invalid json response…’ error.

If this is correct, then the fix in NSS should be simply checking for a trailing slash before appending /.well-known/openid-configuration.

Comece localizando o código que constrói a URL /.well-known/openid-configuration a partir do issuer retornado pela resposta de configuração do OpenID. Adicione cobertura para valores de issuer com e sem uma barra final e confirme que ambos produzem uma URL válida com uma única barra, em vez de uma resposta JSON inválida.