Add CustomTest; update docs

Author: ahinkle

README.md

@@ -228,19 +228,19 @@ $magento->api('products')->show($sku);
 Magento modules can have their own API endpoints.
 For example:
 ```xml
-<route method="POST" url="/V1/custom/save">
+<route method="POST" url="/V1/my-custom-endpoint/save">
     ...
 </route>
-<route method="GET" url="/V1/custom/get/:id">
+<route method="GET" url="/V1/my-custom-endpoint/get/:id">
     ...
 </route>
 ```
 To use these you can directly use get/post methods:
 ```php
-$magento->api('custom')->post('save', [...]);
+$magento->api('my-custom-endpoint')->post('save', [...]);
 ```
 ```php
-$magento->api('custom')->get('get/1');
+$magento->api('my-custom-endpoint')->get('get/1');
 ```
 
 <a id="schema"></a>

tests/Api/CustomTest.php

@@ -0,0 +1,47 @@
+<?php
+
+namespace Grayloon\Magento\Tests;
+
+use Grayloon\Magento\Magento;
+use Illuminate\Support\Facades\Http;
+
+class CustomTest extends TestCase
+{
+    public function test_can_get_custom_endpoint()
+    {
+        Http::fake([
+            '*rest/all/V1/foo/bar' => Http::response([], 200),
+        ]);
+
+        $magento = new Magento();
+        $customApi = $magento->api('/foo')->get('bar');
+
+        $this->assertTrue($customApi->ok());
+    }
+
+    public function test_can_post_custom_endpoint()
+    {
+        Http::fake([
+            '*rest/all/V1/foo/bar' => Http::response([], 200),
+        ]);
+
+        $magento = new Magento();
+        $customApi = $magento->api('/foo')->post('bar');
+
+        $this->assertTrue($customApi->ok());
+    }
+
+    public function test_custom_post_endpoint_passes_params()
+    {
+        Http::fake([
+            '*rest/all/V1/foo/bar' => Http::response([], 200, ['baz' => 'test']),
+        ]);
+
+        $magento = new Magento();
+        $customApi = $magento->api('/foo')->post('bar', [
+            'baz' => 'test',
+        ]);
+
+        $this->assertTrue($customApi->ok());
+    }
+}