add tests for scaling function

pyproject.toml

@@ -14,6 +14,12 @@ classifiers = [
 ]
 dependencies = [
   "requests>=2.0.0",
+  "pytest>=6.0.0",
+]
+
+[tool.pytest.ini_options]
+pythonpath = [
+  ".", "src",
 ]
 
 [project.urls]
@@ -22,4 +28,9 @@ Issues = "https://github.com/a2gov/clarityio/issues"
 
 [build-system]
 requires = ["hatchling"]
-build-backend = "hatchling.build"
+build-backend = "hatchling.build"
+
+[tool.hatch.envs.test]
+dependencies = [
+  "pytest>=6.0.0",
+]

tests/__init__.py

@@ -0,0 +1 @@
+# tests/__init__.py

tests/test_scaling.py

@@ -0,0 +1,30 @@
+import pytest
+import pandas as pd
+import numpy as np
+from clarityio import scale_raw_to_aqi
+
+def test_scale_raw_values():
+    assert scale_raw_to_aqi('pm2.5_24hr', 18.84) == 69.14676806083651
+    assert scale_raw_to_aqi('nitrogen_dioxide_1hr', 300) == 138.64864864864865
+
+def test_scale_pandas_series():
+    data = pd.Series([5, 9, 30, 60])
+    expected = pd.Series([27.777778, 50.0, 89.939163, 154.154506], dtype='float64')
+    result = scale_raw_to_aqi('pm2.5_24hr', data)
+    pd.testing.assert_series_equal(result, expected)
+
+def test_missing_inputs():
+    assert np.isnan(scale_raw_to_aqi('sulfur_dioxide_1hr', None))
+    assert np.isnan(scale_raw_to_aqi('ozone_8hr', np.nan))
+
+def test_invalid_pollutant_name():
+    with pytest.raises(ValueError, match="Unknown pollutant: invalid_pollutant"):
+        scale_raw_to_aqi('invalid_pollutant', 999)
+
+def test_negative_raw_value():
+    with pytest.raises(ValueError, match="Negative pollutant values are invalid."):
+        assert scale_raw_to_aqi('carbon_monoxide_8hr', -0.010) == 0
+
+def test_raw_value_exceeding_scale():
+    with pytest.warns(UserWarning, match="Pollutant value 99999 is off the scale for pm10_24hr, returning maximum scaled value of 500."):
+        assert scale_raw_to_aqi('pm10_24hr', 99999) == 500