From 655ef0c3a8de9ddf763a2a4e843ea8dd32a52680 Mon Sep 17 00:00:00 2001
From: Micah Parks <gpg@micahparks.com>
Date: Thu, 3 Nov 2022 13:01:16 -0400
Subject: [PATCH] Add custom error for invalid ECDSA curve and allow test to
 panic

---
 ecdsa.go      |  8 +++++++-
 ecdsa_test.go | 18 +++++++++---------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/ecdsa.go b/ecdsa.go
index bc0d989..ca0566d 100644
--- a/ecdsa.go
+++ b/ecdsa.go
@@ -3,6 +3,7 @@ package keyfunc
 import (
 	"crypto/ecdsa"
 	"crypto/elliptic"
+	"errors"
 	"fmt"
 	"math/big"
 )
@@ -21,6 +22,11 @@ const (
 	p521 = "P-521"
 )
 
+var (
+	// ErrECDSACurve indicates an error with the ECDSA curve.
+	ErrECDSACurve = errors.New("invalid ECDSA curve")
+)
+
 // ECDSA parses a jsonWebKey and turns it into an ECDSA public key.
 func (j *jsonWebKey) ECDSA() (publicKey *ecdsa.PublicKey, err error) {
 	if j.X == "" || j.Y == "" || j.Curve == "" {
@@ -49,7 +55,7 @@ func (j *jsonWebKey) ECDSA() (publicKey *ecdsa.PublicKey, err error) {
 	case p521:
 		publicKey.Curve = elliptic.P521()
 	default:
-		return nil, fmt.Errorf("unknown curve: %s", j.Curve)
+		return nil, fmt.Errorf("%w: unknown curve: %s", ErrECDSACurve, j.Curve)
 	}
 
 	// Turn the X coordinate into *big.Int.
diff --git a/ecdsa_test.go b/ecdsa_test.go
index 20c4346..c71cacb 100644
--- a/ecdsa_test.go
+++ b/ecdsa_test.go
@@ -1,10 +1,13 @@
-package keyfunc
+package keyfunc_test
 
 import (
 	"encoding/json"
+	"errors"
 	"testing"
 
 	"github.com/golang-jwt/jwt/v4"
+
+	"github.com/MicahParks/keyfunc"
 )
 
 func TestBadCurve(t *testing.T) {
@@ -13,18 +16,15 @@ func TestBadCurve(t *testing.T) {
 		someJWT = `eyJhbGciOiJFUzI1NiIsImtpZCI6IjEiLCJ0eXAiOiJKV1QifQ.e30.Q1EeyWUv6XEA0gMLwTFoNhx7Hq1MbVwjI2k9FZPSa-myKW1wYn1X6rHtRyuV-2MEzvimCskFD-afL7UzvdWBQg`
 	)
 
-	jwks, err := NewJSON(json.RawMessage(badJWKS))
+	jwks, err := keyfunc.NewJSON(json.RawMessage(badJWKS))
 	if err != nil {
 		t.Fatalf("Failed to create JWKS from JSON: %v", err)
 	}
 
-	defer func() {
-		if r := recover(); r != nil {
-			t.Fatalf("panic")
-		}
-	}()
+	// The number of parsed keys should be 0.
 
-	if _, err = jwt.Parse(someJWT, jwks.Keyfunc); err == nil {
-		t.Fatal("No error for bad curve")
+	_, err = jwt.Parse(someJWT, jwks.Keyfunc)
+	if !errors.Is(err, keyfunc.ErrKIDNotFound) {
+		t.Fatalf("Expected ErrKIDNotFound, got %v", err)
 	}
 }