diff --git a/app/Bootstrap/FinderComposer.php b/app/Bootstrap/FinderComposer.php
index cf694f1..461b480 100644
--- a/app/Bootstrap/FinderComposer.php
+++ b/app/Bootstrap/FinderComposer.php
@@ -87,7 +87,10 @@ class FinderComposer
         )->when($this->config->get('app.hide_app_files', true), function (Collection $collection) {
             return $collection->merge(self::APP_FILES);
         })->map(function (string $file) {
-            return glob($file, GLOB_BRACE | GLOB_NOSORT);
+            return glob(
+                $this->container->get('app.root') . '/' . $file,
+                GLOB_BRACE | GLOB_NOSORT
+            );
         })->flatten()->map(function (string $file) {
             return realpath($file);
         });
diff --git a/tests/Unit/Bootstrap/FinderComposerTest.php b/tests/Unit/Bootstrap/FinderComposerTest.php
index e81f29f..7a8b50c 100644
--- a/tests/Unit/Bootstrap/FinderComposerTest.php
+++ b/tests/Unit/Bootstrap/FinderComposerTest.php
@@ -6,17 +6,100 @@ use App\Bootstrap\FinderComposer;
 use DI\Container;
 use PHLAK\Config\Config;
 use PHPUnit\Framework\TestCase;
+use RuntimeException;
 use Symfony\Component\Finder\Finder;
+use Symfony\Component\Finder\SplFileInfo;
 
 class FinderComposerTest extends TestCase
 {
-    public function test_it_can_compose_the_finder_component()
-    {
-        $container = new Container();
-        (new FinderComposer($container, new Config))();
+    /** @var Container The application container */
+    protected $container;
 
-        $finder = $container->get(Finder::class);
+    /** @var Config The application config */
+    protected $config;
+
+    public function setUp(): void
+    {
+        $this->container = new Container();
+        $this->container->set('app.root', realpath(__DIR__ . '/../../files'));
+
+        $this->config = new Config([
+            'app' => [
+                'sort_order' => 'type',
+                'reverse_sort' => false,
+                'hidden_files' => [],
+                'hide_app_files' => true,
+                'hide_vcs_files' => false,
+            ]
+        ]);
+    }
+
+    public function test_it_can_compose_the_finder_component(): void
+    {
+        (new FinderComposer($this->container, $this->config))();
+
+        $finder = $this->container->get(Finder::class);
+        $finder->in($this->container->get('app.root'));
 
         $this->assertInstanceOf(Finder::class, $finder);
+        foreach ($finder as $file) {
+            $this->assertInstanceOf(SplFileInfo::class, $file);
+        }
+    }
+
+    public function test_it_can_sort_by_a_user_provided_closure(): void
+    {
+        $this->config->set('app.sort_order', function (SplFileInfo $file1, SplFileInfo $file2) {
+            return $file1->getSize() <=> $file2->getSize();
+        });
+
+        (new FinderComposer($this->container, $this->config))();
+
+        $finder = $this->container->get(Finder::class);
+        $finder->in($this->container->get('app.root'));
+
+        $this->assertEquals([
+            'alpha.scss',
+            'bravo.js',
+            'echo.yaml',
+            'charlie.bash',
+            'delta.html',
+        ], $this->getFilesArray($finder));
+    }
+
+    public function test_it_can_reverse_the_sort_order()
+    {
+        $this->config->set('app.reverse_sort', true);
+
+        (new FinderComposer($this->container, $this->config))();
+
+        $finder = $this->container->get(Finder::class);
+        $finder->in($this->container->get('app.root'));
+
+        $this->assertEquals([
+            'echo.yaml',
+            'delta.html',
+            'charlie.bash',
+            'bravo.js',
+            'alpha.scss',
+        ], $this->getFilesArray($finder));
+    }
+
+    public function test_it_throws_a_runtime_exception_with_an_invalid_sort_order(): void
+    {
+        $this->config->set('app.sort_order', 'invalid');
+
+        $this->expectException(RuntimeException::class);
+
+        (new FinderComposer($this->container, $this->config))();
+    }
+
+    protected function getFilesArray(Finder $finder): array
+    {
+        $files = array_map(function (SplFileInfo $file) {
+            return $file->getFilename();
+        }, iterator_to_array($finder));
+
+        return array_values($files);
     }
 }
diff --git a/tests/Unit/Controllers/FileInfoControllerTest.php b/tests/Unit/Controllers/FileInfoControllerTest.php
index f376362..828b948 100644
--- a/tests/Unit/Controllers/FileInfoControllerTest.php
+++ b/tests/Unit/Controllers/FileInfoControllerTest.php
@@ -10,14 +10,46 @@ use Slim\Psr7\Response;
 
 class FileInfoControllerTest extends TestCase
 {
-    public function test_it_returns_a_response()
-    {
-        $controller = new FileInfoController(
-            $this->createMock(Config::class)
-        );
+    /** @var Config The application config */
+    protected $config;
 
-        $response = $controller(new Response(), 'tests/files');
+    public function setUp(): void
+    {
+        $this->config = new Config([
+            'app' => [
+                'max_hash_size' => 1000000000
+            ],
+        ]);
+    }
+
+    public function test_it_can_return_a_successful_response()
+    {
+        $controller = new FileInfoController($this->config);
+
+        $response = $controller(new Response(), __DIR__ . '/../../files/alpha.scss');
 
         $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(200, $response->getStatusCode());
+    }
+
+    public function test_it_can_return_a_not_found_response()
+    {
+        $controller = new FileInfoController($this->config);
+
+        $response = $controller(new Response(), 'not_a_file.test');
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(404, $response->getStatusCode());
+    }
+
+    public function test_it_returns_an_error_when_file_size_is_too_large()
+    {
+        $this->config->set('app.max_hash_size', 10);
+        $controller = new FileInfoController($this->config);
+
+        $response = $controller(new Response(), __DIR__ . '/../../files/alpha.scss');
+
+        $this->assertInstanceOf(ResponseInterface::class, $response);
+        $this->assertEquals(500, $response->getStatusCode());
     }
 }
diff --git a/tests/files/alpha.scss b/tests/files/alpha.scss
new file mode 100644
index 0000000..e3097bf
--- /dev/null
+++ b/tests/files/alpha.scss
@@ -0,0 +1,3 @@
+body {
+    background-color: #AC3;
+}
diff --git a/tests/files/bravo.js b/tests/files/bravo.js
new file mode 100644
index 0000000..3c4119b
--- /dev/null
+++ b/tests/files/bravo.js
@@ -0,0 +1 @@
+console.log('Test file; please ignore');
diff --git a/tests/files/charlie.bash b/tests/files/charlie.bash
new file mode 100644
index 0000000..a22b41a
--- /dev/null
+++ b/tests/files/charlie.bash
@@ -0,0 +1,4 @@
+#!/usr/bin/env bash
+set -o errexit
+
+echo "Test file; please ignore"
diff --git a/tests/files/delta.html b/tests/files/delta.html
new file mode 100644
index 0000000..35829c4
--- /dev/null
+++ b/tests/files/delta.html
@@ -0,0 +1,12 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta http-equiv="X-UA-Compatible" content="ie=edge">
+    <title>Document</title>
+</head>
+<body>
+    <h1>Test file; please ignore</h1>
+</body>
+</html>
diff --git a/tests/files/echo.yaml b/tests/files/echo.yaml
new file mode 100644
index 0000000..a3db537
--- /dev/null
+++ b/tests/files/echo.yaml
@@ -0,0 +1,2 @@
+file:
+  contents: 'Test file; please ignore'
diff --git a/tests/files/index.php b/tests/files/index.php
new file mode 100644
index 0000000..d183f7d
--- /dev/null
+++ b/tests/files/index.php
@@ -0,0 +1,3 @@
+<?php
+
+echo 'Test file; please ignore';
diff --git a/tests/files/test.txt b/tests/files/test.txt
deleted file mode 100644
index 702d559..0000000
--- a/tests/files/test.txt
+++ /dev/null
@@ -1 +0,0 @@
-Test file; please ignore