Updated test files to be PSR-4 compliant

Closes #1924

tests/Api/TestsApi.php

@@ -0,0 +1,36 @@
+<?php namespace Tests\Api;
+
+trait TestsApi
+{
+
+    protected $apiTokenId = 'apitoken';
+    protected $apiTokenSecret = 'password';
+
+    /**
+     * Set the API editor role as the current user via the API driver.
+     */
+    protected function actingAsApiEditor()
+    {
+        $this->actingAs($this->getEditor(), 'api');
+        return $this;
+    }
+
+    /**
+     * Format the given items into a standardised error format.
+     */
+    protected function errorResponse(string $message, int $code): array
+    {
+        return ["error" => ["code" => $code, "message" => $message]];
+    }
+
+    /**
+     * Get an approved API auth header.
+     */
+    protected function apiAuthHeader(): array
+    {
+        return [
+            "Authorization" => "Token {$this->apiTokenId}:{$this->apiTokenSecret}"
+        ];
+    }
+
+}