Add a test for carbon footprint estimation

cats/carbonFootprint.py

@@ -8,13 +8,15 @@ def get_footprint_reduction_estimate(
     PUE: float,
     jobinfo: list[tuple[int, float]],
     runtime: datetime.timedelta,
-    average_best_ci: float,
+    average_best_ci: float,  # in gCO2/kWh
     average_now_ci: float,
 ) -> Estimates:
+    # energy in kWh
     energy = (
         PUE
         * (runtime.total_seconds() / 3600)
-        * sum([(nunits * power) / 1000 for nunits, power in jobinfo])
+        * sum([(nunits * power) for nunits, power in jobinfo])
+        / 1000
     )
     best = energy * average_best_ci
     now = energy * average_now_ci

tests/test_footprint.py

@@ -0,0 +1,17 @@
+import datetime
+
+from cats.carbonFootprint import Estimates, get_footprint_reduction_estimate
+
+JOBINFO = [(1, 2.0), (2, 3.0), (8, 1.0)]
+
+
+def test_get_footprint_reduction_estimate():
+    expected = Estimates(now="3 gCO2e", best="2 gCO2e", savings="gCO2e")
+    est = get_footprint_reduction_estimate(
+        PUE=1.0,
+        jobinfo=JOBINFO,
+        runtime=datetime.timedelta(minutes=60),
+        average_best_ci=150,  # gCO2/kWh
+        average_now_ci=200,  # gCO2/kWh
+    )
+    assert est == expected