Improve cookie tests code coverage (#918)

context_test.go

@@ -384,12 +384,21 @@ func TestContextSetCookie(t *testing.T) {
 	assert.Equal(t, c.Writer.Header().Get("Set-Cookie"), "user=gin; Path=/; Domain=localhost; Max-Age=1; HttpOnly; Secure")
 }
 
+func TestContextSetCookiePathEmpty(t *testing.T) {
+	c, _ := CreateTestContext(httptest.NewRecorder())
+	c.SetCookie("user", "gin", 1, "", "localhost", true, true)
+	assert.Equal(t, c.Writer.Header().Get("Set-Cookie"), "user=gin; Path=/; Domain=localhost; Max-Age=1; HttpOnly; Secure")
+}
+
 func TestContextGetCookie(t *testing.T) {
 	c, _ := CreateTestContext(httptest.NewRecorder())
 	c.Request, _ = http.NewRequest("GET", "/get", nil)
 	c.Request.Header.Set("Cookie", "user=gin")
 	cookie, _ := c.Cookie("user")
 	assert.Equal(t, cookie, "gin")
+
+	_, err := c.Cookie("nokey")
+	assert.Error(t, err)
 }
 
 func TestContextBodyAllowedForStatus(t *testing.T) {