Add unstable as valid api version (bold-commerce#119)

Co-authored-by: Craig Dykstra <[email protected]>

goshopify.go

@@ -22,6 +22,8 @@ import (
 
 const (
 	UserAgent = "goshopify/1.0.0"
+	// UnstableApiVersion Shopify API version for accessing unstable API features
+	UnstableApiVersion = "unstable"
 
 	// Shopify API version YYYY-MM - defaults to admin which uses the oldest stable version of the api
 	defaultApiPathPrefix = "admin"
@@ -87,7 +89,7 @@ type Client struct {
 	Customer                   CustomerService
 	CustomerAddress            CustomerAddressService
 	Order                      OrderService
-	Fulfillment		   FulfillmentService
+	Fulfillment                FulfillmentService
 	DraftOrder                 DraftOrderService
 	Shop                       ShopService
 	Webhook                    WebhookService

options.go

@@ -9,7 +9,7 @@ type Option func(c *Client)
 func WithVersion(apiVersion string) Option {
 	return func(c *Client) {
 		pathPrefix := defaultApiPathPrefix
-		if len(apiVersion) > 0 && apiVersionRegex.MatchString(apiVersion) {
+		if len(apiVersion) > 0 && (apiVersionRegex.MatchString(apiVersion) || apiVersion == UnstableApiVersion) {
 			pathPrefix = fmt.Sprintf("admin/api/%s", apiVersion)
 		}
 		c.apiVersion = apiVersion

options_test.go

@@ -53,3 +53,11 @@ func TestWithLogger(t *testing.T) {
 		t.Errorf("WithLogger expected logs to match %v != %v", c.log, logger)
 	}
 }
+
+func TestWithUnstableVersion(t *testing.T) {
+	c := NewClient(app, "fooshop", "abcd", WithVersion(UnstableApiVersion))
+	expected := fmt.Sprintf("admin/api/%s", UnstableApiVersion)
+	if c.pathPrefix != expected {
+		t.Errorf("WithVersion client.pathPrefix = %s, expected %s", c.pathPrefix, expected)
+	}
+}