diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..4abe429
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1766807290,
+        "narHash": "sha256-7sgUQMKMDvpeu9cwE7mWJfP9N3wJduunmJ/s8LOd9nk=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "4eec65df50d796a8fd9c146a09b5007916ce376b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/src/animaltrack/cli.py b/src/animaltrack/cli.py
index 7839a06..b9965d3 100644
--- a/src/animaltrack/cli.py
+++ b/src/animaltrack/cli.py
@@ -15,14 +15,10 @@ def main():
 
     # migrate command
     migrate_parser = subparsers.add_parser("migrate", help="Run database migrations")
-    migrate_parser.add_argument(
-        "--to", type=str, help="Migrate to specific version", default=None
-    )
+    migrate_parser.add_argument("--to", type=str, help="Migrate to specific version", default=None)
 
     # create-migration command
-    create_parser = subparsers.add_parser(
-        "create-migration", help="Create a new migration file"
-    )
+    create_parser = subparsers.add_parser("create-migration", help="Create a new migration file")
     create_parser.add_argument("description", help="Description for the migration")
 
     # seed command
diff --git a/tests/conftest.py b/tests/conftest.py
index 5f22522..97aa702 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,9 +1,10 @@
 # ABOUTME: Pytest configuration and fixtures for AnimalTrack tests.
 # ABOUTME: Provides database fixtures, test clients, and common utilities.
 
-import pytest
-import tempfile
 import os
+import tempfile
+
+import pytest
 
 
 @pytest.fixture
diff --git a/tests/test_placeholder.py b/tests/test_placeholder.py
new file mode 100644
index 0000000..ad7d3ea
--- /dev/null
+++ b/tests/test_placeholder.py
@@ -0,0 +1,7 @@
+# ABOUTME: Placeholder test to ensure test infrastructure works.
+# ABOUTME: Remove once real tests are added.
+
+
+def test_placeholder():
+    """Placeholder test - remove when real tests exist."""
+    assert True