Fixed panic for bearer token factory (#40)

basculehttp/tokenFactory.go

@@ -105,7 +105,8 @@ func (btf BearerTokenFactory) ParseAndValidate(ctx context.Context, _ *http.Requ
 	}
 
 	leewayclaims := bascule.ClaimsWithLeeway{
-		Leeway: btf.Leeway,
+		MapClaims: make(jwt.MapClaims),
+		Leeway:    btf.Leeway,
 	}
 
 	jwsToken, err := btf.Parser.ParseJWT(value, &leewayclaims, keyfunc)

jws.go

@@ -26,7 +26,7 @@ func (parser defaultJWTParser) ParseJWT(token string, claims jwt.Claims, parseFu
 var DefaultJWTParser JWTParser = defaultJWTParser{}
 
 type ClaimsWithLeeway struct {
-	*jwt.MapClaims
+	jwt.MapClaims
 	Leeway Leeway
 }
 

jws_test.go

@@ -0,0 +1,22 @@
+package bascule
+
+import (
+	"testing"
+
+	jwt "github.com/dgrijalva/jwt-go"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValid(t *testing.T) {
+	assert := assert.New(t)
+	claims := ClaimsWithLeeway{
+		MapClaims: make(jwt.MapClaims),
+		Leeway: Leeway{
+			EXP: 5,
+			NBF: 5,
+			IAT: 5,
+		},
+	}
+	err := claims.Valid()
+	assert.Nil(err)
+}