take the sig algorithm from the key

registry.go

@@ -106,6 +106,13 @@ func Clear() {
 	}
 }
 
+func nowFromClock(clock jwt.Clock) time.Time {
+	if clock == nil {
+		return time.Now()
+	}
+	return clock.Now()
+}
+
 // Sign will create a new JWT based on the map of input data,
 // the Context's configuration, and current signing key.  If the
 // signing key name is not set, an error will be returned.
@@ -139,18 +146,11 @@ func Sign(purpose string, claims map[string]string, clock jwt.Clock) (signed []b
 		return
 	}
 
-	var now time.Time
-	if clock != nil {
-		now = clock.Now()
-	} else {
-		now = time.Now()
-	}
-
+	now := nowFromClock(clock)
 	builder := &jwt.Builder{}
 	builder = builder.
 		Claim(jwt.IssuerKey, c.issuer).
 		Claim(jwt.IssuedAtKey, now)
-
 	if c.signingValidityPeriod > 0 {
 		builder = builder.Claim(jwt.ExpirationKey, now.Add(c.signingValidityPeriod))
 	}
@@ -166,7 +166,7 @@ func Sign(purpose string, claims map[string]string, clock jwt.Clock) (signed []b
 		}
 	}
 
-	signed, err = jwt.Sign(t, jwa.HS256, key)
+	signed, err = jwt.Sign(t, jwa.SignatureAlgorithm(key.Algorithm()), key)
 	return
 }
 

registry_test.go

@@ -180,6 +180,7 @@ func setupKeys(t *testing.T) {
 
 func TestSign(t *testing.T) {
 	setupKeys(t)
+	t.Parallel()
 	type args struct {
 		purpose string
 		claims  map[string]string
@@ -274,6 +275,7 @@ func TestSign(t *testing.T) {
 
 func TestValidate(t *testing.T) {
 	setupKeys(t)
+	t.Parallel()
 	type args struct {
 		purpose string
 		signed  []byte
@@ -362,3 +364,29 @@ func TestValidate(t *testing.T) {
 		})
 	}
 }
+
+func timeEqualsEpislion(want time.Time, got time.Time, fudge time.Duration) bool {
+	return got.Unix() >= want.Add(-fudge).Unix() && got.Unix() <= want.Add(fudge).Unix()
+}
+
+func Test_nowFromClock(t *testing.T) {
+	type args struct {
+		clock jwt.Clock
+	}
+	tests := []struct {
+		name string
+		args args
+		want time.Time
+	}{
+		{"nil", args{nil}, time.Now()},
+		{"set at 50", args{&TimeClock{50}}, time.Unix(50, 0)},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := nowFromClock(tt.args.clock)
+			if !timeEqualsEpislion(tt.want, got, 1*time.Second) {
+				t.Errorf("nowFromClock() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}