mymax: step 01, misstep

ramalho · ramalho · commit 71626432b284 · 2021-03-23T16:21:51.000-03:00
diff --git a/less_than/max_steps/01-two_numbers/01-misstep/mymax.py b/less_than/max_steps/01-two_numbers/01-misstep/mymax.py
@@ -0,0 +1,23 @@
+"""
+Q: Why not define ``Number`` as follows?
+
+::
+    Number = Union[float, Decimal, Fraction]
+
+
+A: Because ``Union`` is not helpful as a return type.
+
+    "Be conservative in what you send, be liberal in what you accept."
+    —Postel's Law
+
+"""
+
+from decimal import Decimal
+from fractions import Fraction
+from typing import Union
+
+Number = Union[float, Decimal, Fraction]
+
+
+def max(a: Number, b: Number) -> Number:
+    return a if a >= b else b
diff --git a/less_than/max_steps/01-two_numbers/01-misstep/mymax_test.py b/less_than/max_steps/01-two_numbers/01-misstep/mymax_test.py
@@ -0,0 +1,39 @@
+from decimal import Decimal
+from fractions import Fraction
+
+import mymax
+from mymax import Number
+
+import pytest
+
+
+@pytest.mark.parametrize(
+    'a, b, expected',
+    [
+        (1, 2, 2),
+        (-3, -1, -1),
+        (4, 4, 4),
+    ],
+)
+def test_two_ints(a: int, b: int, expected: int) -> None:
+    result = mymax.max(a, b)
+    assert result == expected
+
+
+def test_two_numbers() -> None:
+    result = mymax.max(Fraction(1, 3), Fraction(1, 4))
+    assert result == Fraction(1, 3)
+
+
+@pytest.mark.parametrize(
+    'a, b, expected',
+    [
+        (1, 2, 2),
+        (0.1, 0.01, 0.1),
+        (Fraction(1, 3), Fraction(1, 2), Fraction(1, 2)),
+        (Decimal('-1.3'), Decimal('-1.2'), Decimal('-1.2')),
+    ],
+)
+def test_two_numbers_params(a: Number, b: Number, expected: Number) -> None:
+    result = mymax.max(a, b)
+    assert result == expected
diff --git a/less_than/max_steps/01-two_numbers/01-misstep/mypy.ini b/less_than/max_steps/01-two_numbers/01-misstep/mypy.ini
@@ -0,0 +1,6 @@
+[mypy]
+python_version = 3.9
+warn_unused_configs = True
+disallow_incomplete_defs = True
+[mypy-pytest]
+ignore_missing_imports = True
