diff --git a/test/AgeDirTest.php b/test/AgeDirTest.php
new file mode 100644
index 0000000..f03d2f7
--- /dev/null
+++ b/test/AgeDirTest.php
@@ -0,0 +1,32 @@
+<?php declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+final class AgeDirTest extends TestCase
+{
+    public function setUp(): void
+    {
+        prepare_testing_dir();
+        exec('php dir2cast.php --output=out.xml --dont-uncache --ignore-dir2cast-mtime');
+    }
+
+    public function test_age_dir()
+    {
+        $mtime1 = filemtime('dir2cast.php');
+        $mtime2 = filemtime('temp');
+        $mtime3 = filemtime('.');
+        $mtime4 = filemtime('out.xml');
+
+        age_dir_by('.', 10);
+
+        $this->assertEquals($mtime1 - 10, filemtime('dir2cast.php'));
+        $this->assertEquals($mtime2 - 10, filemtime('temp'));
+        $this->assertEquals($mtime3 - 10, filemtime('.'));
+        $this->assertEquals($mtime4 - 10, filemtime('out.xml'));
+    }
+
+    public function tearDown(): void
+    {
+        chdir('..');
+    }
+}
\ No newline at end of file
diff --git a/test/CachingTest.php b/test/CachingTest.php
index 4b8217a..35b5212 100644
--- a/test/CachingTest.php
+++ b/test/CachingTest.php
@@ -2,7 +2,7 @@
 
 use PHPUnit\Framework\TestCase;
 
-final class CachingTest extends TestCase
+class CachingTest extends TestCase
 {
     public $file = 'out.xml';
     public $output = '';
@@ -18,21 +18,6 @@ public function setUp(): void
         clearstatcache();
     }
 
-    public function test_age_dir()
-    {
-        $mtime1 = filemtime('dir2cast.php');
-        $mtime2 = filemtime('temp');
-        $mtime3 = filemtime('.');
-        $mtime4 = filemtime('out.xml');
-
-        age_dir_by('.', 10);
-
-        $this->assertEquals($mtime1 - 10, filemtime('dir2cast.php'));
-        $this->assertEquals($mtime2 - 10, filemtime('temp'));
-        $this->assertEquals($mtime3 - 10, filemtime('.'));
-        $this->assertEquals($mtime4 - 10, filemtime('out.xml'));
-    }
-
     public function test_default_empty_podcast_caches_output_in_default_folder(): void
     {
         // caches the output in the default temp folder
diff --git a/test/CachingTest_prepopulatedTest.php b/test/CachingTest_prepopulatedTest.php
new file mode 100644
index 0000000..730cae4
--- /dev/null
+++ b/test/CachingTest_prepopulatedTest.php
@@ -0,0 +1,22 @@
+<?php declare(strict_types=1);
+
+use PHPUnit\Framework\TestCase;
+
+class CachingTest_prepopulatedTest extends CachingTest
+{
+    public function setUp(): void
+    {
+        prepare_testing_dir();
+        file_put_contents('pre-existing.mp3', 'test');
+        touch('pre-existing.mp3', time()-86400);
+        exec('php dir2cast.php --output=out.xml --dont-uncache --ignore-dir2cast-mtime', $this->output, $this->returncode);
+        $this->content = file_get_contents($this->file);
+        clearstatcache();
+    }
+
+    public function tearDown(): void
+    {
+        $this->assertEquals(1, preg_match('/pre-existing\.mp3/', file_get_contents($this->file)));
+        parent::tearDown();
+    }
+}