diff --git a/src/EnvReader/EnvConfig.php b/src/EnvReader/EnvConfig.php
index 81637bb..e52dd2d 100644
--- a/src/EnvReader/EnvConfig.php
+++ b/src/EnvReader/EnvConfig.php
@@ -4,9 +4,7 @@ namespace jrosset\EnvReader;
 
 use Exception;
 
-abstract class EnvConfig extends GenericConfig {
-    use TExternalFile;
-
+abstract class EnvConfig extends GenericConfig implements IExternalConfigFile {
     /**
      * @inheritDoc
      */
diff --git a/src/EnvReader/TExternalFile.php b/src/EnvReader/IExternalConfigFile.php
similarity index 53%
rename from src/EnvReader/TExternalFile.php
rename to src/EnvReader/IExternalConfigFile.php
index f075648..6505bd6 100644
--- a/src/EnvReader/TExternalFile.php
+++ b/src/EnvReader/IExternalConfigFile.php
@@ -3,13 +3,13 @@
 namespace jrosset\EnvReader;
 
 /**
- * Trait for config based on an external file
+ * Interface for config based on an external file
  */
-trait TExternalFile {
+interface IExternalConfigFile {
     /**
      * Get the external config file path
      *
      * @return string The config file path
      */
-    protected abstract function getConfigFilePath (): string;
+    public function getConfigFilePath (): string;
 }
\ No newline at end of file
diff --git a/tests/test_env.php b/tests/test_env.php
index b148c5e..8ee92f7 100644
--- a/tests/test_env.php
+++ b/tests/test_env.php
@@ -12,7 +12,7 @@ class Env extends EnvConfig {
             'WEBSITE_NAME' => 'Generic site',
         ];
     }
-    protected function getConfigFilePath (): string {
+    public function getConfigFilePath (): string {
         return __DIR__ . '/.env';
     }
 }