diff --git a/pyproject.toml b/pyproject.toml
index b8df0e9..9904f62 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [tool.setuptools.packages.find]
 where = ["src"]
-include = ["otf"]
+include = ["otf*"]
 
 [project]
 name = "otf-api"
@@ -32,3 +32,16 @@ dependencies = [
     "pydantic==2.7.3",
     "pycognito==2024.5.1",
 ]
+
+
+[project.optional-dependencies]
+dev = [
+    "pytest==8.2.2",
+    "pytest-loguru==0.4.0",
+    "pytest-asyncio==0.23.7",
+    "aioresponses==0.7.6",
+    "tox==4.15.1",
+]
+
+[tools.pytest.ini_options]
+pythonpath = ["src"]
diff --git a/tests/test_api.py b/tests/test_api.py
new file mode 100644
index 0000000..2c04fba
--- /dev/null
+++ b/tests/test_api.py
@@ -0,0 +1,8 @@
+import pytest
+from otf.api import Api
+
+
+@pytest.mark.asyncio
+async def test_api_raises_error_if_no_username_password():
+    with pytest.raises(TypeError):
+        await Api.create()
diff --git a/tox.ini b/tox.ini
index 223985a..a775f84 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,8 +1,10 @@
 [tox]
+skipsdist=True
 envlist = py310, py311
 
 [testenv]
+recreate = False
 deps = 
-    pytest
+    .[dev]
 commands = 
-    pytest
+    pytest
\ No newline at end of file