Fix tests

get_group_size: drop tests
get_group: change usage to pass group_count, not group_size
Test across range of sizes, not just 32
Use set operations to test coverage
Use itertools.chain idiom to simplify code

tests/test_groups.py

@@ -1,50 +1,37 @@
-import pytest
-
-from pytest_test_groups import get_group, get_group_size
-
-
-def test_group_size_computed_correctly_for_even_group():
-    expected = 8
-    actual = get_group_size(32, 4)  # 32 total tests; 4 groups
-
-    assert expected == actual
-
+from itertools import chain
 
-def test_group_size_computed_correctly_for_odd_group():
-    expected = 8
-    actual = get_group_size(31, 4)  # 31 total tests; 4 groups
+import pytest
 
-    assert expected == actual
+from pytest_test_groups import get_group
 
 
 def test_group_is_the_proper_size():
     items = [str(i) for i in range(32)]
     group = get_group(items, 8, 1)
 
-    assert len(group) == 8
+    assert len(group) == 4
 
 
 def test_all_groups_together_form_original_set_of_tests():
-    items = [str(i) for i in range(32)]
-
-    groups = [get_group(items, 8, i) for i in range(1, 5)]
-
-    combined = []
-    for group in groups:
-        combined.extend(group)
-
-    assert combined == items
+    group_count = 8
+    for item_size in range(group_count, 32):
+        items = [str(i) for i in range(item_size)]
+        groups = [get_group(items, group_count, i) for i in range(1, group_count + 1)]
+        combined = set(chain.from_iterable(groups))
+        assert combined == set(items)
 
 
 def test_group_that_is_too_high_raises_value_error():
     items = [str(i) for i in range(32)]
 
     with pytest.raises(ValueError):
-        get_group(items, 8, 5)
+        # When group_count=4, group_id=5 is out of bounds
+        get_group(items, 4, 5)
 
 
 def test_group_that_is_too_low_raises_value_error():
     items = [str(i) for i in range(32)]
 
     with pytest.raises(ValueError):
-        get_group(items, 8, 0)
+        # When group_count=4, group_id=0 is out of bounds
+        get_group(items, 4, 0)