Added property-based tests, please rename accordingly!

pytest.ini

+# pytest.ini
+[pytest]
+addopts = --doctest-modules --hypothesis-show-statistics
+testpaths =
+    zerosumset
+    tests
+markers = 
+    timing_test    

tests/tests_zerosumsets.py

@@ -13,3 +13,26 @@ def test_zerosumset(elems):
     assert output == elems, f"Failed: expected {elems}"
 
 
+from hypothesis import given, strategies as st, event, assume
+
+from random import randint
+
+@st.composite
+def gen_solvable(draw, min_size=5, max_size=10):
+    xs = draw(st.lists(st.integers(), min_size=5, max_size=10))
+    n  = draw(st.integers(min_value=1))
+    l  = len(xs)
+    pos1 = randint(0, l-1)
+    xs.insert(pos1, n)
+    pos2 = randint(0, l)
+    xs.insert(pos2, -n)
+    return xs
+
+@given(gen_solvable())
+# @given(st.lists(st.integers(), min_size=5, max_size=10).filter(lambda xs: not all(x > 0 for x in xs)))
+def test_sum_is_zero(xs):
+    # assume(not all(x > 0 for x in xs))
+    subxs = zerosumset(xs)
+    if not subxs: event("null result")
+    assert sum(subxs) == 0, f"Result doesn't have zero sum: {subxs}"
+