diff --git a/src/Console/Command/GenerateCommand.php b/src/Console/Command/GenerateCommand.php
index 6de81d7..0ea5751 100644
--- a/src/Console/Command/GenerateCommand.php
+++ b/src/Console/Command/GenerateCommand.php
@@ -8,6 +8,7 @@ use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
+use Symfony\Component\Filesystem\Exception\IOException;
 
 class GenerateCommand extends Command
 {
@@ -44,10 +45,14 @@ class GenerateCommand extends Command
             throw new \Exception('No filters.php file found.');
         }
 
-        // TOOD: Check return code.
-        new Builder($filters, $outputFile);
-
         $io = new SymfonyStyle($input, $output);
-        $io->success(sprintf('%s file generated.', $outputFile));
+
+        try {
+            new Builder($filters, $outputFile);
+
+            $io->success(sprintf('%s file generated.', $outputFile));
+        } catch (IOException $e) {
+            $io->error($e->getMessage());
+        }
     }
 }
diff --git a/src/Service/Builder.php b/src/Service/Builder.php
index f8cf70f..9acdbb7 100644
--- a/src/Service/Builder.php
+++ b/src/Service/Builder.php
@@ -19,10 +19,21 @@ class Builder
      */
     private $outputFile;
 
-    public function __construct(array $filters, $outputFile = 'filters.xml') {
+    /**
+     * @var bool
+     */
+    private $writeFile;
+
+    /**
+     * @var string
+     */
+    private $xml;
+
+    public function __construct(array $filters, $outputFile = 'filters.xml', $writeFile = true) {
         $this->filesystem = new Filesystem();
         $this->filters = $filters;
         $this->outputFile = $outputFile;
+        $this->writeFile = $writeFile;
 
         $this->build();
     }
@@ -32,6 +43,16 @@ class Builder
         return $this->build();
     }
 
+    /**
+     * Returns the generated XML.
+     *
+     * @return string
+     */
+    public function getXml()
+    {
+        return $this->xml;
+    }
+
     /**
      * Build XML for a set of filters.
      *
@@ -46,9 +67,11 @@ class Builder
             return $this->buildEntry($items);
         })->implode(PHP_EOL);
 
-        $content = collect([$prefix, $xml, $suffix])->implode(PHP_EOL);
+        $this->xml = collect([$prefix, $xml, $suffix])->implode(PHP_EOL);
 
-        $this->filesystem->dumpFile($this->outputFile, $content);
+        if ($this->writeFile) {
+            $this->filesystem->dumpFile($this->outputFile, $this->xml);
+        }
     }
 
     /**
diff --git a/tests/Unit/BuilderTest.php b/tests/Unit/BuilderTest.php
index 25f24d3..cf70229 100644
--- a/tests/Unit/BuilderTest.php
+++ b/tests/Unit/BuilderTest.php
@@ -18,7 +18,7 @@ class BuilderTest extends TestCase
             ->star()
             ->important();
 
-        $result = new Builder([$filterA, $filterB]);
+        $result = new Builder([$filterA, $filterB], '', false);
 
         $expected = <<<EOF
 <?xml version='1.0' encoding='UTF-8'?>
@@ -36,6 +36,6 @@ class BuilderTest extends TestCase
 </feed>
 EOF;
 
-        $this->assertEquals($expected, $result->__toString());
+        $this->assertEquals($expected, $result->getXml());
     }
 }