* Make Amount arithmetic more generic
To modify generated amounts, we need some extra operations on `Amount`.
We also need to extend existing operations to both `NonNegative` and
`NegativeAllowed` amounts.
* Add a constrain method for ValueBalance
* Derive Eq for ValueBalance
* impl Neg for ValueBalance
* Make some Amount arithmetic expectations explicit
* Explain why we use i128 for multiplication
And expand the overflow error details.
* Expand Amount::sum error details
* Make amount::Error field order consistent
* Rename an amount::Error variant to Constraint, so it's clearer
* Add specific pool variants to ValueBalanceError
* add serialization for value balances
* change test names
* change panic messages
* add a deserialization test
* return the errors from `from_bytes()` methods
* add prop test for serialize/deserialize Amount
* Move amount proptests to amount::tests::prop
Co-authored-by: teor <teor@riseup.net>
* add a zero() method to Amount
* add a value balance type
* change some docs
* rename methods
* Doc changes
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
* add getters and setters for `ValueBalance`
* remove commented out code
* impl Add for ValueBalance
* split the tests
* change tests
* fix derives
* change default() to zero()
* remove default constraint
* use matches!
* separate testing code into submodules
* change mod struct
Co-authored-by: Janito Vaqueiro Ferreira Filho <janito.vff@gmail.com>
teor
Conrado Gouvea
Alfredo Garcia