I can show and hide the columns comanger

.claude/commands/unit-tester.md

@@ -685,6 +685,56 @@ assert matches(element, expected)
 
 ---
 
+### UTR-16: Propose Parameterized Tests
+
+**Rule:** When proposing a test plan, systematically identify tests that can be parameterized and propose them as such.
+
+**When to parameterize:**
+- Tests that follow the same pattern with different input values
+- Tests that verify the same behavior for different sides/directions (left/right, up/down)
+- Tests that check the same logic with different states (visible/hidden, enabled/disabled)
+- Tests that validate the same method with different valid inputs
+
+**How to identify candidates:**
+1. Look for tests with similar names differing only by a value (e.g., `test_left_panel_...` and `test_right_panel_...`)
+2. Look for tests that have identical structure but different parameters
+3. Look for combinatorial scenarios (side × state combinations)
+
+**How to propose:**
+In your test plan, explicitly show:
+1. The individual tests that would be written without parameterization
+2. The parameterized version with all test cases
+3. The reduction in test count
+
+**Example proposal:**
+
+```
+**Without parameterization (4 tests):**
+- test_i_can_toggle_left_panel_from_visible_to_hidden
+- test_i_can_toggle_left_panel_from_hidden_to_visible
+- test_i_can_toggle_right_panel_from_visible_to_hidden
+- test_i_can_toggle_right_panel_from_hidden_to_visible
+
+**With parameterization (1 test, 4 cases):**
+@pytest.mark.parametrize("side, initial, expected", [
+    ("left", True, False),
+    ("left", False, True),
+    ("right", True, False),
+    ("right", False, True),
+])
+def test_i_can_toggle_panel_visibility(...)
+
+**Result:** 1 test instead of 4, same coverage
+```
+
+**Benefits:**
+- Reduces code duplication
+- Makes it easier to add new test cases
+- Improves maintainability
+- Makes the test matrix explicit
+
+---
+
 ## Managing Rules
 
 To disable a specific rule, the user can say: