diff --git a/README.md b/README.md
index b073ce1..ab64c4f 100644
--- a/README.md
+++ b/README.md
@@ -57,6 +57,8 @@ Any output from this script is prefixed with `[php-watcher]`, otherwise all
 PHP-Watcher supports customization of its behavior with config files. The
  file for options may be named `.php-watcher.yml`, `php-watcher.yml` or `php
  -watcher.yml.dist`. The tool will look for a file in the current working directory in that order. 
+An alternative local configuration file can be specified with the `--config
+ <file>` option.
 
 The specificity is as follows, so that a command line argument will always override the config file settings:
 
diff --git a/tests/ConfigTest.php b/tests/ConfigTest.php
new file mode 100644
index 0000000..0f6438d
--- /dev/null
+++ b/tests/ConfigTest.php
@@ -0,0 +1,36 @@
+<?php declare(strict_types=1);
+
+namespace tests;
+
+use tests\Helper\Filesystem;
+use tests\Helper\WatcherRunner;
+use tests\Helper\WatcherTestCase;
+
+final class ConfigTest extends WatcherTestCase
+{
+    /** @test */
+    public function command_line_options_override_config_values(): void
+    {
+        $configFile = Filesystem::createConfigFile(['watch' => ['directory-to-watch']]);
+        $fileToWatch = Filesystem::createHelloWorldPHPFile();
+
+        $watcher = (new WatcherRunner())->run($fileToWatch, ['--watch', 'tests', '--config', $configFile]);
+        sleep(1);
+
+        $output = $watcher->getOutput();
+        $this->assertStringNotContainsString('directory-to-watch', $output);
+    }
+
+    /** @test */
+    public function it_can_use_config_path_from_command_line_arg(): void
+    {
+        $configFile = Filesystem::createConfigFile(['watch' => ['directory-to-watch']]);
+        $fileToWatch = Filesystem::createHelloWorldPHPFile();
+
+        $watcher = (new WatcherRunner())->run($fileToWatch, ['--config', $configFile]);
+        sleep(1);
+
+        $output = $watcher->getOutput();
+        $this->assertStringContainsString('directory-to-watch', $output);
+    }
+}