Enable PHP 7.2 build

[giorgiosironi]

See #114

[giorgiosironi]

The Mersenne Twister implementation seems to have a syntax problem:

Error: Failure evaluating code: 
$this->mt[$i] <= $this->wMask

Ah right:

PHPUnit\Framework\Error\Deprecated: assert(): Calling assert() with a string argument is deprecated

[SkUrRiEr]

Interestingly running the unit tests locally under PHP 7.2 on my Debian Testing box didn't show any of those failures, only the one I patched in my PR. (And running under HHVM didn't show the errors I patched in that PR either)

[giorgiosironi]

I think the exceptions spawn from deprecations so they may depend on the underlying PHP configuration.

[peter279k]

The assert function is deprecated on php-7.2.
The more details are in the official PHP doc.

According to the Travis CI build log, it seems that the src/Random/MersenneTwister.php on line 54 should be modified, too.

[localheinz]

@giorgiosironi

@peter279k is right, running

$ git grep "assert('"

on this branch yields

src/Random/MersenneTwister.php:54:        assert('$this->index <= $this->n');
src/Random/MersenneTwister.php:60:        assert('$y <= 0xffffffff');
src/Random/MersenneTwister.php:62:        assert('$y <= 0xffffffff');
src/Random/MersenneTwister.php:64:        assert('$y <= 0xffffffff');
src/Random/MersenneTwister.php:66:        assert('$y <= 0xffffffff');
src/Random/MersenneTwister.php:81:            assert('$x <= 0xffffffff');
src/Random/MersenneTwister.php:83:            assert('$xA <= 0x7fffffff');

[giorgiosironi]

I guess these should be replaced by https://github.com/beberlei/assert

[peter279k]

@giorgiosironi , thank you for your reply.
I think we should modify the passed argument for assert function because the assert function pass argument is changed since php-7.2.

According to the official PHP doc, the warning message for php-7.2 is as follows:

Warning
Using string as the assertion is DEPRECATED as of PHP 7.2.

I don't think it's necessary to add another Assert package to do this 👍 .

[giorgiosironi]

Is that backward compatible with how assert was used in the other supported versions? I'll try that out.