diff --git a/tests/test_helpers.py b/tests/test_helpers.py
index 87ef134..c532f5f 100644
--- a/tests/test_helpers.py
+++ b/tests/test_helpers.py
@@ -1,18 +1,58 @@
+import pytest
+
 from pigeon_magnet_solver.helpers import (_fix_exes, _rotate_r, _valid_rotate,
                                           rotate_r)
 
 
-def test_rotate_r():
-    assert _rotate_r(list("1x01")) == list("11x0")
-    assert _rotate_r(list("11x0")) == list("011x")
-    assert _rotate_r(list("011x")) == list("x011")
-    assert _rotate_r(list("x011")) == list("1x01")
+@pytest.mark.parametrize("test_input,expected", [
+    # trivial cases
+    ("1111", "1111"),
+    ("0000", "0000"),
+    ("xxxx", "xxxx"),
 
-    assert _valid_rotate(list("1x01"), list("11x0")) is False
-    assert _valid_rotate(list("1x01"), list("011x")) is False
-    assert _valid_rotate(list("1x01"), list("x011")) is True
-    assert _valid_rotate(list("1x01"), list("1x01")) is True
+    # interesting case "1x01"
+    ("1x01", "11x0"),
+    ("11x0", "011x"),
+    ("011x", "x011"),
+    ("x011", "1x01"),
+])
+def test__rotate_r(test_input: str, expected: str):
+    assert _rotate_r(list(test_input)) == list(expected)
 
+
+@pytest.mark.parametrize("test_input,candidate,expected", [
+    # interesting case "1x01"
+    ("1x01", "11x0", False),
+    ("1x01", "011x", False),
+    ("1x01", "x011", True),
+    ("1x01", "1x01", True),
+])
+def test__valid_rotate(test_input: str, candidate: str, expected: bool):
+    assert _valid_rotate(list(test_input), list(candidate)) is expected
+
+
+def test__fix_exes():
     assert _fix_exes(list("1x01"), list("x011")) == list("0x11")
 
-    assert rotate_r(list("1x01")) == list("0x11")
+
+@pytest.mark.parametrize("test_input,expected", [
+    # trivial cases
+    ("1111", "1111"),
+    ("0000", "0000"),
+    ("xxxx", "xxxx"),
+
+    # fixpoints "1x10"
+    ("1x10", "1x10"),
+    ("101x", "101x"),
+    ("1x1x", "1x1x"),
+
+    # alternating case "1010"
+    ("1010", "0101"),
+    ("0101", "1010"),
+
+    # interesting case "1x01"
+    ("1x01", "0x11"),
+    ("0x11", "1x01"),
+])
+def test_rotate_r(test_input: str, expected: str):
+    assert rotate_r(list(test_input)) == list(expected)