We should fix all these warnings, by adding the additional braces as required.
```
../../src/test/amount_tests.cpp:87:38: warning: suggest braces around initialization of subobject [-Wmissing-braces]
std::array<int64_t, 8> values = {-23, -1, 0, 1, 2, 3, 42, 99999999};
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
{ }
```