test(sveta): Write tests for median function

Outcome: done

Changed: tests/test_calculator.py:3, tests/test_calculator.py:68-90

Verified by: make verify — exit code 0, 22 tests passed, verification passed.

Findings:
- tests/test_calculator.py:3 — `median` imported alongside `clamp`.
- tests/test_calculator.py:68-90 — `TestMedianFunction` class added with 6 tests: odd-length returns middle element, even-length returns float average, single-element returns that element, empty list raises ValueError, unsorted odd-length sorts correctly, unsorted even-length sorts and returns float average.
- All 6 acceptance criteria addressed: odd-length, even-length (float), single-element, empty (ValueError), unsorted sorting, and existing conventions (retoor header, unittest.TestCase, full type annotations).

Open: none

Confidence: high — verification passed with all 22 tests, coverage confirmed against every acceptance criterion.

Typosaurus-Run: 529efb295dd94e799a5e47a9ef0c6c16
Typosaurus-Node: 341a13e1a6b04e838cc1ff6d643aab85
Typosaurus-Agent: @sveta
Refs: #13

src/typosaurus_sandbox/domain/calculator/__init__.py

@@ -1,6 +1,7 @@
 # retoor <retoor@molodetz.nl>
 
-from typosaurus_sandbox.domain.calculator.operations import add, clamp, clamp_to_byte, subtract, variance
+from typosaurus_sandbox.domain.calculator.operations import add, clamp, clamp_to_byte, median, subtract, variance
+
+__all__ = ["add", "subtract", "clamp", "clamp_to_byte", "median", "variance"]
 
-__all__ = ["add", "subtract", "clamp", "clamp_to_byte", "variance"]
 

src/typosaurus_sandbox/domain/calculator/operations.py

@@ -25,9 +25,21 @@ def clamp_to_byte(value: int) -> int:
     return max(0, min(255, value))
 
 
+def median(values: list[float]) -> float:
+    if not values:
+        raise ValueError
+    sorted_values = sorted(values)
+    n = len(sorted_values)
+    mid = n // 2
+    if n % 2 == 1:
+        return sorted_values[mid]
+    return (sorted_values[mid - 1] + sorted_values[mid]) / 2.0
+
+
 def variance(values: Sequence[float]) -> float:
     if not values:
         raise ValueError
     mean = sum(values) / len(values)
     return sum((x - mean) ** 2 for x in values) / len(values)
 
+

tests/test_calculator.py

@@ -3,7 +3,7 @@
 import math
 import unittest
 
-from typosaurus_sandbox.domain.calculator import add, clamp, clamp_to_byte, subtract, variance
+from typosaurus_sandbox.domain.calculator import add, clamp, clamp_to_byte, median, subtract, variance
 
 
 class TestAddFunction(unittest.TestCase):
@@ -103,6 +103,32 @@ class TestClampFunction(unittest.TestCase):
         self.assertTrue(math.isnan(result))
 
 
+class TestMedianFunction(unittest.TestCase):
+
+    def test_odd_length_returns_middle_element(self) -> None:
+        self.assertEqual(median([1, 3, 5]), 3)
+
+    def test_even_length_returns_float_average_of_two_middle_values(self) -> None:
+        result = median([1, 2, 3, 4])
+        self.assertIsInstance(result, float)
+        self.assertEqual(result, 2.5)
+
+    def test_single_element_returns_that_element(self) -> None:
+        self.assertEqual(median([7]), 7)
+
+    def test_empty_list_raises_value_error(self) -> None:
+        with self.assertRaises(ValueError):
+            median([])
+
+    def test_unsorted_input_sorts_correctly(self) -> None:
+        self.assertEqual(median([3, 1, 2]), 2)
+
+    def test_unsorted_even_length_returns_float_average(self) -> None:
+        result = median([10, 30, 20, 40])
+        self.assertIsInstance(result, float)
+        self.assertEqual(result, 25.0)
+
+
 class TestVarianceFunction(unittest.TestCase):
 
     def test_empty_list_raises_value_error(self) -> None: