diff --git a/.coveragerc b/.coveragerc
new file mode 100644
index 0000000..ed17307
--- /dev/null
+++ b/.coveragerc
@@ -0,0 +1,13 @@
+[run]
+branch = True
+omit =
+  kassalappy/cli.py
+
+[report]
+exclude_lines =
+    pragma: no cover
+    def __repr__
+    def __str__
+    def __rich_console__
+    if __name__ == .__main__.:
+    if TYPE_CHECKING
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..2cafca1
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,34 @@
+run := poetry run
+
+.PHONY: test
+test:
+	$(run) pytest tests/ $(ARGS)
+
+.PHONY: test-coverage
+test-coverage:
+	$(run) pytest tests/ --cov-report term-missing --cov=kassalappy $(ARGS)
+
+.PHONY: coverage
+coverage:
+	$(run) coverage html
+
+.PHONY: format
+format:
+	$(run) ruff format kassalappy
+
+.PHONY: format-check
+format-check:
+	$(run) ruff --check kassalappy
+
+.PHONY: setup
+setup:
+	poetry install
+
+.PHONY: update
+update:
+	poetry update
+
+.PHONY: repl
+repl:
+	$(run) python
+
diff --git a/kassalappy/const.py b/kassalappy/const.py
index 207840a..5e3c36b 100644
--- a/kassalappy/const.py
+++ b/kassalappy/const.py
@@ -1,10 +1,11 @@
 """Constants used by kassalapp."""
 
 from http import HTTPStatus
-from importlib.metadata import version
 from typing import Final
 
-VERSION = version("kassalappy")
+from .version import __version__
+
+VERSION = __version__
 
 API_ENDPOINT: Final = "https://kassal.app/api/v1"
 DEFAULT_TIMEOUT: Final = 10
diff --git a/kassalappy/models.py b/kassalappy/models.py
index 5cb62f3..f99bd95 100644
--- a/kassalappy/models.py
+++ b/kassalappy/models.py
@@ -3,6 +3,7 @@
 from abc import ABC
 from dataclasses import dataclass, field
 from datetime import datetime
+from enum import Enum
 import logging
 from typing import ClassVar, Literal
 
@@ -11,10 +12,36 @@
 from mashumaro.mixins.orjson import DataClassORJSONMixin
 from typing_extensions import TypedDict
 
-from .typing import StrEnum
-
 _LOGGER = logging.getLogger()
 
+
+# noinspection PyUnresolvedReferences
+class StrEnum(str, Enum):
+    """A string enumeration of type `(str, Enum)`.
+    All members are compared via `upper()`. Defaults to UNKNOWN.
+    """
+
+    def __str__(self) -> str:
+        return str(self.value)
+
+    def __eq__(self, other: str) -> bool:
+        other = other.upper()
+        return super().__eq__(other)
+
+    @classmethod
+    def _missing_(cls, value) -> str:
+        has_unknown = False
+        for member in cls:
+            if member.name.upper() == "UNKNOWN":
+                has_unknown = True
+            if member.name.upper() == value.upper():
+                return member
+        if has_unknown:
+            _LOGGER.warning("'%s' is not a valid '%s'", value, cls.__name__)
+            return cls.UNKNOWN
+        raise ValueError(f"'{value}' is not a valid {cls.__name__}")
+
+
 Unit = Literal[
     "cl",
     "cm",
diff --git a/kassalappy/typing.py b/kassalappy/typing.py
deleted file mode 100644
index c55d0f2..0000000
--- a/kassalappy/typing.py
+++ /dev/null
@@ -1,33 +0,0 @@
-from __future__ import annotations
-
-from enum import Enum
-import logging
-
-_LOGGER = logging.getLogger(__name__)
-
-
-# noinspection PyUnresolvedReferences
-class StrEnum(str, Enum):
-    """A string enumeration of type `(str, Enum)`.
-    All members are compared via `upper()`. Defaults to UNKNOWN.
-    """
-
-    def __str__(self) -> str:
-        return str(self.value)
-
-    def __eq__(self, other: str) -> bool:
-        other = other.upper()
-        return super().__eq__(other)
-
-    @classmethod
-    def _missing_(cls, value) -> str:
-        has_unknown = False
-        for member in cls:
-            if member.name.upper() == "UNKNOWN":
-                has_unknown = True
-            if member.name.upper() == value.upper():
-                return member
-        if has_unknown:
-            _LOGGER.warning("'%s' is not a valid '%s'", value, cls.__name__)
-            return cls.UNKNOWN
-        raise ValueError(f"'{value}' is not a valid {cls.__name__}")
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..d1694aa
--- /dev/null
+++ b/tests/__init__.py
@@ -0,0 +1,5 @@
+"""kassalappy tests."""
+
+import pytest
+
+pytestmark = pytest.mark.asyncio(loop_scope="package")
diff --git a/tests/conftest.py b/tests/conftest.py
new file mode 100644
index 0000000..de61820
--- /dev/null
+++ b/tests/conftest.py
@@ -0,0 +1,31 @@
+from __future__ import annotations
+
+import logging
+from typing import Callable
+
+from aiohttp import ClientSession
+
+import pytest
+
+from kassalappy import Kassalapp
+
+_LOGGER = logging.getLogger(__name__)
+
+
+@pytest.fixture
+async def kassalapp_client(default_access_token) -> Callable[..., Kassalapp]:
+    """Return Politikontroller Client."""
+
+    def _kassalapp_client(
+        access_token: str | None = None,
+        session: ClientSession | None = None,
+    ) -> Kassalapp:
+        token = access_token if access_token is not None else default_access_token
+        return Kassalapp(access_token=token, websession=session)
+
+    return _kassalapp_client
+
+
+@pytest.fixture
+def default_access_token():
+    return "baba"
diff --git a/tests/fixtures/health.json b/tests/fixtures/health.json
new file mode 100644
index 0000000..873901f
--- /dev/null
+++ b/tests/fixtures/health.json
@@ -0,0 +1 @@
+{"data":{"status":"ok"}}
diff --git a/tests/helpers.py b/tests/helpers.py
new file mode 100644
index 0000000..ceb614a
--- /dev/null
+++ b/tests/helpers.py
@@ -0,0 +1,21 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import orjson
+
+FIXTURE_DIR = Path(__file__).parent / "fixtures"
+
+
+def load_fixture(name: str) -> str:
+    """Load a fixture."""
+    path = FIXTURE_DIR / f"{name}.json"
+    if not path.exists():  # pragma: no cover
+        raise FileNotFoundError(f"Fixture {name} not found")
+    return path.read_text(encoding="utf-8")
+
+
+def load_fixture_json(name: str) -> dict | list:
+    """Load a fixture as JSON."""
+    data = load_fixture(name)
+    return orjson.loads(data)
diff --git a/tests/ruff.toml b/tests/ruff.toml
new file mode 100644
index 0000000..078aa64
--- /dev/null
+++ b/tests/ruff.toml
@@ -0,0 +1,17 @@
+# This extends our general Ruff rules specifically for tests
+extend = "../pyproject.toml"
+
+lint.extend-select = [
+    "PT", # Use @pytest.fixture without parentheses
+]
+
+lint.extend-ignore = [
+    "S101",
+    "S106",
+    "S108",
+    "SLF001",
+    "TCH002",
+    "PLR2004",
+]
+
+lint.pylint.max-branches = 13
diff --git a/tests/test_api.py b/tests/test_api.py
new file mode 100644
index 0000000..3f86963
--- /dev/null
+++ b/tests/test_api.py
@@ -0,0 +1,25 @@
+"""Tests for NrkPodcastAPI."""
+
+from __future__ import annotations
+
+import logging
+
+from aiohttp import ClientSession
+from aiohttp.web_response import json_response
+from aresponses import Response, ResponsesMockServer
+
+from kassalappy.models import StatusResponse
+from .helpers import load_fixture_json
+
+logger = logging.getLogger(__name__)
+
+
+async def test_health(aresponses: ResponsesMockServer, kassalapp_client):
+    aresponses.add(
+        response=json_response(load_fixture_json("health")),
+    )
+    async with ClientSession() as session:
+        client = kassalapp_client(session=session)
+        result = await client.healthy()
+        assert isinstance(result, StatusResponse)
+        assert result.status == "ok"