diff --git a/spec/Gaufrette/Adapter/DoctrineDbalSpec.php b/spec/Gaufrette/Adapter/DoctrineDbalSpec.php
index e78a3f7f..e55c73c3 100644
--- a/spec/Gaufrette/Adapter/DoctrineDbalSpec.php
+++ b/spec/Gaufrette/Adapter/DoctrineDbalSpec.php
@@ -154,7 +154,7 @@ function it_calculates_checksum(Connection $connection)
             ->$method('SELECT "checksum" FROM "someTableName" WHERE "key" = :key', ['key' => 'filename'])
             ->willReturn(1234);
 
-        $this->checksum('filename')->shouldReturn(1234);
+        $this->checksum('filename')->shouldReturn("1234");
     }
 
     function it_gets_mtime(Connection $connection)
diff --git a/spec/Gaufrette/Adapter/FlysystemSpec.php b/spec/Gaufrette/Adapter/FlysystemSpec.php
index 26ce5270..bf0c0031 100644
--- a/spec/Gaufrette/Adapter/FlysystemSpec.php
+++ b/spec/Gaufrette/Adapter/FlysystemSpec.php
@@ -34,7 +34,7 @@ function it_writes_file(AdapterInterface $adapter, Config $config)
     {
         $adapter->write('filename', 'Hello.', $config)->willReturn([]);
 
-        $this->write('filename', 'Hello.')->shouldReturn([]);
+        $this->write('filename', 'Hello.')->shouldReturn(0);
     }
 
     function it_checks_if_file_exists(AdapterInterface $adapter)
diff --git a/src/Gaufrette/Adapter/Flysystem.php b/src/Gaufrette/Adapter/Flysystem.php
index cfabad98..fc8dc53d 100644
--- a/src/Gaufrette/Adapter/Flysystem.php
+++ b/src/Gaufrette/Adapter/Flysystem.php
@@ -37,7 +37,17 @@ public function read(string $key): string|bool
      */
     public function write(string $key, mixed $content): int|bool
     {
-        return $this->adapter->write($key, $content, $this->config);
+        $metadata = $this->adapter->write($key, $content, $this->config);
+
+        if (false === $metadata) {
+            return false;
+        }
+
+        if (is_int($metadata['size'] ?? 0)) {
+            return $metadata['size'] ?? 0;
+        }
+
+        return 0;
     }
 
     /**