in src/Assert.hack [492:508]
public function assertRegExp(
string $expected,
string $actual,
string $message = '',
): void {
if (\preg_match($expected, $actual) === 1) {
return;
}
throw new ExpectationFailedException(
Str\format(
"%s\nFailed asserting that %s matches PCRE pattern %s",
$message,
$actual,
$expected,
),
);
}