diff --git a/checksum-command.php b/checksum-command.php
index be4607bea..128faf07c 100644
--- a/checksum-command.php
+++ b/checksum-command.php
@@ -4,7 +4,7 @@
 	return;
 }
 
-$wpcli_checksum_autoloader = dirname( __FILE__ ) . '/vendor/autoload.php';
+$wpcli_checksum_autoloader = __DIR__ . '/vendor/autoload.php';
 if ( file_exists( $wpcli_checksum_autoloader ) ) {
 	require_once $wpcli_checksum_autoloader;
 }
@@ -14,4 +14,3 @@
 
 WP_CLI::add_command( 'plugin', 'Plugin_Command_Namespace' );
 WP_CLI::add_command( 'plugin verify-checksums', 'Checksum_Plugin_Command' );
-
diff --git a/composer.json b/composer.json
index a990818b5..95d357a18 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     },
     "require-dev": {
         "wp-cli/extension-command": "^1.2 || ^2",
-        "wp-cli/wp-cli-tests": "^3.1"
+        "wp-cli/wp-cli-tests": "^4"
     },
     "config": {
         "process-timeout": 7200,
diff --git a/src/Checksum_Plugin_Command.php b/src/Checksum_Plugin_Command.php
index c65a80b62..99a8b942d 100644
--- a/src/Checksum_Plugin_Command.php
+++ b/src/Checksum_Plugin_Command.php
@@ -101,13 +101,13 @@ public function __invoke( $args, $assoc_args ) {
 			$version = empty( $version_arg ) ? $this->get_plugin_version( $plugin->file ) : $version_arg;
 
 			if ( in_array( $plugin->name, $exclude_list, true ) ) {
-				$skips++;
+				++$skips;
 				continue;
 			}
 
 			if ( false === $version ) {
 				WP_CLI::warning( "Could not retrieve the version for plugin {$plugin->name}, skipping." );
-				$skips++;
+				++$skips;
 				continue;
 			}
 
@@ -122,7 +122,7 @@ public function __invoke( $args, $assoc_args ) {
 
 			if ( false === $checksums ) {
 				WP_CLI::warning( "Could not retrieve the checksums for version {$version} of plugin {$plugin->name}, skipping." );
-				$skips++;
+				++$skips;
 				continue;
 			}
 
diff --git a/src/WP_CLI/Fetchers/UnfilteredPlugin.php b/src/WP_CLI/Fetchers/UnfilteredPlugin.php
index 92781db5d..794ef3c53 100644
--- a/src/WP_CLI/Fetchers/UnfilteredPlugin.php
+++ b/src/WP_CLI/Fetchers/UnfilteredPlugin.php
@@ -36,4 +36,3 @@ public function get( $name ) {
 		return false;
 	}
 }
-