We have code inside LibWeb that uses the
`AK::StringUtils::convert_to_uint`and `AK::StringUtils::convert_to_int`
methods for parsing integers. This works well for the most part, but
according to the spec, trailing characters are allowed and should be
ignored, but this is not how the `StringUtil` methods are implemented.
This patch adds two new methods named `parse_integer` and
`parse_non_negative_integer` inside the `Web::HTML` namespace that uses
`StringUtils` under the hood but adds a bit more logic to make it spec
compliant.
After the CSSPixels implementation evolved from a wrapper of double
to a fixed-point saturated math arithmetic implementation, it makes
sense to have separate tests for it.
Using a file(GLOB) to find all the test files in a directory is an easy
hack to get things started, but has some drawbacks. Namely, if you add
a test, it won't be found again without re-running CMake. `ninja` seems
to do this automatically, but it would be nice to one day stop seeing it
rechecking our globbed directories.
The test suite includes a few basic tests and a very crude regression
test, which just concatenates the to_string() of all tokens and checks
the String's hash to be equal. This relies on the format of
HTMLToken::to_string() to stay the same, which is not ideal.
