Added ConfigProvider tests

- Ensure expected dependencies are provided.

Author: weierophinney

test/ConfigProviderTest.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace ProblemDetailsTest;
+
+use PHPUnit\Framework\TestCase;
+use ProblemDetails\ConfigProvider;
+use ProblemDetails\ProblemDetailsMiddleware;
+use ProblemDetails\ProblemDetailsMiddlewareFactory;
+use ProblemDetails\ProblemDetailsResponseFactory;
+use ProblemDetails\ProblemDetailsResponseFactoryFactory;
+
+class ConfigProviderTest extends TestCase
+{
+    public function testReturnsExpectedDependencies()
+    {
+        $provider = new ConfigProvider();
+        $config = $provider();
+
+        $this->assertArrayHasKey('dependencies', $config);
+
+        $dependencies = $config['dependencies'];
+        $this->assertArrayHasKey('factories', $dependencies);
+
+        $factories = $dependencies['factories'];
+        $this->assertCount(2, $factories);
+        $this->assertArrayHasKey(ProblemDetailsMiddleware::class, $factories);
+        $this->assertArrayHasKey(ProblemDetailsResponseFactory::class, $factories);
+
+        $this->assertSame(
+            ProblemDetailsMiddlewareFactory::class,
+            $factories[ProblemDetailsMiddleware::class]
+        );
+        $this->assertSame(
+            ProblemDetailsResponseFactoryFactory::class,
+            $factories[ProblemDetailsResponseFactory::class]
+        );
+    }
+}