client.go: Fix issue with how platform is set on call() (#5)

purchases_test.go

@@ -42,3 +42,26 @@ func TestCreatePurchaseWithOpts(t *testing.T) {
 	cl.expectXPlatform(t, "ios")
 	cl.expectBody(t, `{"app_user_id":"123","fetch_token":"testreceipt","product_id":"product_sku","is_restore":true}`)
 }
+
+func TestCreatePurchaseWithStripe(t *testing.T) {
+	cl := newMockClient(t, 200, nil, nil)
+	rc := New("apikey")
+	rc.http = cl
+
+	opt := &CreatePurchaseOptions{
+		Platform: string(StripeStore),
+
+		ProductID: "product_sku",
+		IsRestore: true,
+	}
+
+	_, err := rc.CreatePurchase("123", "testreceipt", opt)
+	if err != nil {
+		t.Errorf("error: %v", err)
+	}
+
+	cl.expectMethod(t, "POST")
+	cl.expectPath(t, "/v1/receipts")
+	cl.expectXPlatform(t, "stripe")
+	cl.expectBody(t, `{"app_user_id":"123","fetch_token":"testreceipt","product_id":"product_sku","is_restore":true}`)
+}