test: experimenting with hypothesis for property-based testing

.gitignore

@@ -8,3 +8,4 @@ dist
 venv*
 .*cache
 coverage_html
+.hypothesis

pyproject.toml

@@ -39,6 +39,7 @@ pylint = "^2.4.4"
 black = "^22.1.0"
 ruff = "^0.0.254"
 pyupgrade = "^3.3.1"
+hypothesis = "^6.75.2"
 
 [tool.ruff]
 ignore = ["E402", "E501"]

tests/test_transforms_hypot.py

@@ -0,0 +1,27 @@
+"""
+Tests of aw-core transforms using hypothesis
+"""
+
+from datetime import datetime, timedelta
+
+from aw_core.models import Event
+from hypothesis import assume, given
+from hypothesis import strategies as st
+
+
+@st.composite
+def events(draw, min_start=datetime.min):
+    start = draw(st.datetimes(min_value=min_start, timezones=st.timezones()))
+    duration = draw(st.timedeltas(min_value=timedelta(seconds=0)))
+    title = draw(st.text())
+
+    return Event(timestamp=start, duration=duration, data={"title": title})
+
+
+@given(eventlist=st.lists(events(), min_size=1))
+def test_sum_durations(eventlist):
+    from aw_transform import sum_durations
+
+    assert sum_durations(eventlist) == sum(
+        [e.duration for e in eventlist], timedelta(seconds=0)
+    )