add tests for money amount

tests/tests_unit/test_money_amount.py

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+from decimal import Decimal
+
+import pytest
+from money.currency import Currency
+
+from xexe.money_amount import MoneyAmount
+
+
+def test_money_amount_simple_creation_works():
+
+    an_amount = MoneyAmount(amount=10, currency=Currency.USD)
+
+    assert an_amount.amount == 10
+    assert an_amount.currency == Currency.USD
+
+
+def test_money_amount_takes_integer_amounts():
+    an_amount = MoneyAmount(amount=10, currency=Currency.USD)
+
+    assert an_amount.amount == 10
+
+
+def test_money_amount_takes_decimal_amounts():
+    an_amount = MoneyAmount(amount=Decimal(10.5), currency=Currency.USD)
+
+    assert an_amount.amount == Decimal(10.5)
+
+
+def test_money_amount_takes_proper_strings_amounts():
+    an_amount = MoneyAmount(amount="10.55", currency=Currency.USD)
+
+    assert an_amount.amount == Decimal(10.55)
+
+
+def test_money_amount_fails_with_ugly_strings():
+    with pytest.raises(ValueError):
+        MoneyAmount(amount="not a nuuuuumber", currency=Currency.USD)
+
+
+def test_money_amount_takes_string_for_currency():
+    an_amount = MoneyAmount(amount="10.55", currency="USD")
+
+    assert an_amount.currency == Currency.USD
+
+
+def test_money_amount_works_with_8_decimal_positions():
+    an_amount = MoneyAmount(amount="1.12345678", currency="USD")
+
+    assert an_amount == Decimal(1.12345678)