Testing

The library's tests

tests/Unit holds CurrencyTest, MoneyTest and SchemaOrgTest: known and refused codes, precision, localized names and symbols; arithmetic and comparison in one currency and refused across two; every overflow, PHP_INT_MIN included; decimals read and printed for currencies of 0, 2 and 3 digits, up to the largest amount; allocations with remainders, ties, zero ratios and negative amounts; the schema.org MonetaryAmount and Offer price, decimals kept as text.

From the root of the monorepo:

vendor/bin/phpunit packages/money/tests

Installed on its own:

composer install
vendor/bin/phpunit --no-configuration tests

Mutation testing holds the library to the bar of a domain layer: every mutant of src/ is killed.

Testing code that counts money

• Assert on minor units, not on decimals or formatted strings: self::assertSame(1_234, $total->minorUnits).
• Keep a currency of each precision in the cases that compute: JPY (0), CAD (2), BHD (3). A computation that assumes 2 decimals fails on the yen.
• Assert that the parts of a split add up to the whole: Money::sum(...$parts)->equals($amount).
• Money has no clock, container or I/O: no double is needed.