google: support scopes for JWT access token

Change-Id: I11acd87a56cd003fdb68a5a687e37df450c400d1
GitHub-Last-Rev: efb2e8a08a
GitHub-Pull-Request: golang/oauth2#504
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/327929
Trust: Shin Fan <shinfan@google.com>
Trust: Cody Oss <codyoss@google.com>
Run-TryBot: Shin Fan <shinfan@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cody Oss <codyoss@google.com>

google/jwt_test.go

@@ -13,29 +13,21 @@ import (
 	"encoding/json"
 	"encoding/pem"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
 	"golang.org/x/oauth2/jws"
 )
 
-func TestJWTAccessTokenSourceFromJSON(t *testing.T) {
-	// Generate a key we can use in the test data.
-	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
-	if err != nil {
-		t.Fatal(err)
-	}
+var (
+	privateKey *rsa.PrivateKey
+	jsonKey    []byte
+	once       sync.Once
+)
 
-	// Encode the key and substitute into our example JSON.
-	enc := pem.EncodeToMemory(&pem.Block{
-		Type:  "PRIVATE KEY",
-		Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
-	})
-	enc, err = json.Marshal(string(enc))
-	if err != nil {
-		t.Fatalf("json.Marshal: %v", err)
-	}
-	jsonKey := bytes.Replace(jwtJSONKey, []byte(`"super secret key"`), enc, 1)
+func TestJWTAccessTokenSourceFromJSON(t *testing.T) {
+	setupDummyKey(t)
 
 	ts, err := JWTAccessTokenSourceFromJSON(jsonKey, "audience")
 	if err != nil {
@@ -89,3 +81,80 @@ func TestJWTAccessTokenSourceFromJSON(t *testing.T) {
 		t.Errorf("Header KeyID = %q, want %q", got, want)
 	}
 }
+
+func TestJWTAccessTokenSourceWithScope(t *testing.T) {
+	setupDummyKey(t)
+
+	ts, err := JWTAccessTokenSourceWithScope(jsonKey, "scope1", "scope2")
+	if err != nil {
+		t.Fatalf("JWTAccessTokenSourceWithScope: %v\nJSON: %s", err, string(jsonKey))
+	}
+
+	tok, err := ts.Token()
+	if err != nil {
+		t.Fatalf("Token: %v", err)
+	}
+
+	if got, want := tok.TokenType, "Bearer"; got != want {
+		t.Errorf("TokenType = %q, want %q", got, want)
+	}
+	if got := tok.Expiry; tok.Expiry.Before(time.Now()) {
+		t.Errorf("Expiry = %v, should not be expired", got)
+	}
+
+	err = jws.Verify(tok.AccessToken, &privateKey.PublicKey)
+	if err != nil {
+		t.Errorf("jws.Verify on AccessToken: %v", err)
+	}
+
+	claim, err := jws.Decode(tok.AccessToken)
+	if err != nil {
+		t.Fatalf("jws.Decode on AccessToken: %v", err)
+	}
+
+	if got, want := claim.Iss, "gopher@developer.gserviceaccount.com"; got != want {
+		t.Errorf("Iss = %q, want %q", got, want)
+	}
+	if got, want := claim.Sub, "gopher@developer.gserviceaccount.com"; got != want {
+		t.Errorf("Sub = %q, want %q", got, want)
+	}
+	if got, want := claim.Scope, "scope1 scope2"; got != want {
+		t.Errorf("Aud = %q, want %q", got, want)
+	}
+
+	// Finally, check the header private key.
+	parts := strings.Split(tok.AccessToken, ".")
+	hdrJSON, err := base64.RawURLEncoding.DecodeString(parts[0])
+	if err != nil {
+		t.Fatalf("base64 DecodeString: %v\nString: %q", err, parts[0])
+	}
+	var hdr jws.Header
+	if err := json.Unmarshal([]byte(hdrJSON), &hdr); err != nil {
+		t.Fatalf("json.Unmarshal: %v (%q)", err, hdrJSON)
+	}
+
+	if got, want := hdr.KeyID, "268f54e43a1af97cfc71731688434f45aca15c8b"; got != want {
+		t.Errorf("Header KeyID = %q, want %q", got, want)
+	}
+}
+
+func setupDummyKey(t *testing.T) {
+	once.Do(func() {
+		// Generate a key we can use in the test data.
+		pk, err := rsa.GenerateKey(rand.Reader, 2048)
+		if err != nil {
+			t.Fatal(err)
+		}
+		privateKey = pk
+		// Encode the key and substitute into our example JSON.
+		enc := pem.EncodeToMemory(&pem.Block{
+			Type:  "PRIVATE KEY",
+			Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
+		})
+		enc, err = json.Marshal(string(enc))
+		if err != nil {
+			t.Fatalf("json.Marshal: %v", err)
+		}
+		jsonKey = bytes.Replace(jwtJSONKey, []byte(`"super secret key"`), enc, 1)
+	})
+}