diff --git a/igelfs/filesystem.py b/igelfs/filesystem.py
index aad0993..cb46121 100644
--- a/igelfs/filesystem.py
+++ b/igelfs/filesystem.py
@@ -214,7 +214,7 @@ def get_info(self, lxos_config: LXOSParser | None = None) -> dict[str, Any]:
             "path": self.path.as_posix(),
             "size": self.size,
             "section_count": self.section_count,
-            "partition_minors": sorted(self.partition_minors),
+            "partition_minors": sorted(self.partition_minors_by_directory),
         }
         if lxos_config:
             info["partition_names"] = [
diff --git a/igelfs/tests/test_filesystem.py b/igelfs/tests/test_filesystem.py
new file mode 100644
index 0000000..0ac16a2
--- /dev/null
+++ b/igelfs/tests/test_filesystem.py
@@ -0,0 +1,11 @@
+"""Unit tests for the filesystem class."""
+
+import pytest
+
+from igelfs import Filesystem
+
+
+@pytest.mark.slow
+def test_filesystem_partition_minors(filesystem: Filesystem) -> None:
+    """Test getting partition minors from filesystem."""
+    assert filesystem.partition_minors == filesystem.partition_minors_by_directory
diff --git a/pyproject.toml b/pyproject.toml
index d513ea9..50d8e7c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -42,5 +42,6 @@ warn_unused_ignores = true
 
 [tool.pytest.ini_options]
 markers = [
-    "inf: tests require LXOS configuration file"
+  "inf: tests require LXOS configuration file",
+  "slow: tests take a while to complete",
 ]