As recommended, an `internal/assert` package was added with a reduced set of assertions. All tests were then refactored to use the internal assertions. When more complex assertions were used, they have been rewritten using logic and the simplified assertions.
Fancy formatting for failures was omitted. The `internal/assert/assertions.diff` function could be overwritten for better formatting. That is where diff libraries are used in other test suites.
Refs: #872
Co-authored-by: Alex Mikitik <alex.mikitik@oracle.com>
Parser did not track the location of the faulty inline table in the
document, and unmarshaler tried to the use the non-raw data field of the
AST node, both resulting into a panic when generating the parser error.
Fixes#850