Flatten budget-app contents into repo root

backend/tests/test_calc.py

@@ -0,0 +1,30 @@
+from decimal import Decimal
+
+import pytest
+
+from app.calc import ExpressionError, evaluate, even_spread
+
+
+@pytest.mark.parametrize("text,expected", [
+    ("=5512*12", "66144"),
+    ("3292.56+(12*839.67)+(12*148.19)", "15146.88"),
+    ("4 839,65", "4839.65"),
+    ("1.234,50", "1234.50"),
+    ("1,234.50", "1234.50"),
+    ("", "0"),
+    ("-10/4", "-2.5"),
+])
+def test_evaluate(text, expected):
+    assert evaluate(text) == Decimal(expected)
+
+
+@pytest.mark.parametrize("text", ["__import__('os')", "2**10", "1/0", "abc", "1;2"])
+def test_evaluate_rejects(text):
+    with pytest.raises(ExpressionError):
+        evaluate(text)
+
+
+def test_even_spread_adds_up():
+    months = even_spread(Decimal("100.00"))
+    assert sum(months) == Decimal("100.00")
+    assert months[0] == Decimal("8.33") and months[-1] == Decimal("8.37")