test(sveta): Write clamp tests

Outcome: done
Changed: tests/__init__.py:1, tests/test_calculator.py:1-86
Verified by: `make verify` — exit 0, "verification passed", Ran 16 tests in 0.001s, OK
Findings: tests/ directory created at ./tests/ with __init__.py (header only) and test_calculator.py (16 tests for clamp).
Findings: All 16 clamp tests pass under `make verify`: value below low, above high, in range, equals low, equals high, low>high ValueError, negative values, float below/above/in-range/equals-boundary, float low>high ValueError, large values, -inf/inf boundaries, and NaN.
Findings: clamp is typed as (value: int, low: int, high: int) -> int; float and inf/NaN tests pass because Python does not enforce type hints at runtime.
Open: none
Confidence: high - all 16 tests pass, all acceptance criteria covered, make verify passes

Typosaurus-Run: 5b5c36bf38254bf4bfcdbde317991a5a
Typosaurus-Node: 56f03705c3d64023ba102d3aa3169ef2
Typosaurus-Agent: @sveta
Refs: #7

tests/__init__.py

@@ -0,0 +1 @@
+# retoor <retoor@molodetz.nl>

tests/test_calculator.py

@@ -0,0 +1,63 @@
+# retoor <retoor@molodetz.nl>
+
+import math
+import unittest
+
+from src.calculator import clamp
+
+
+class TestClampFunction(unittest.TestCase):
+
+    def test_value_below_low_returns_low(self) -> None:
+        self.assertEqual(clamp(-5, 0, 10), 0)
+
+    def test_value_above_high_returns_high(self) -> None:
+        self.assertEqual(clamp(15, 0, 10), 10)
+
+    def test_value_in_range_returns_value(self) -> None:
+        self.assertEqual(clamp(5, 0, 10), 5)
+
+    def test_value_equals_low_returns_low(self) -> None:
+        self.assertEqual(clamp(0, 0, 10), 0)
+
+    def test_value_equals_high_returns_high(self) -> None:
+        self.assertEqual(clamp(10, 0, 10), 10)
+
+    def test_low_greater_than_high_raises_value_error(self) -> None:
+        with self.assertRaises(ValueError):
+            clamp(5, 10, 0)
+
+    def test_all_negative_values(self) -> None:
+        self.assertEqual(clamp(-10, -5, -1), -5)
+
+    def test_float_value_below_low_returns_low_as_int(self) -> None:
+        self.assertEqual(clamp(-1.0, 0, 10), 0)
+
+    def test_float_value_above_high_returns_high_as_int(self) -> None:
+        self.assertEqual(clamp(15.0, 0, 10), 10)
+
+    def test_float_value_in_range_returns_float(self) -> None:
+        result = clamp(5.0, 0, 10)
+        self.assertIsInstance(result, float)
+        self.assertEqual(result, 5.0)
+
+    def test_float_value_equals_boundary_returns_boundary(self) -> None:
+        self.assertEqual(clamp(0.0, 0, 10), 0)
+        self.assertEqual(clamp(10.0, 0, 10), 10)
+
+    def test_float_low_greater_than_float_high_raises_value_error(self) -> None:
+        with self.assertRaises(ValueError):
+            clamp(5.0, 10.0, 0.0)
+
+    def test_large_values(self) -> None:
+        self.assertEqual(clamp(10**9, 0, 10**6), 10**6)
+
+    def test_negative_infinity_not_clamped_by_default(self) -> None:
+        self.assertEqual(clamp(-math.inf, 0, 10), 0)
+
+    def test_positive_infinity_not_clamped_by_default(self) -> None:
+        self.assertEqual(clamp(math.inf, 0, 10), 10)
+
+    def test_nan_returns_nan(self) -> None:
+        result = clamp(math.nan, 0, 10)
+        self.assertTrue(math.isnan(result))