This is the PHP port of Hamcrest Matchers
Hamcrest is a matching library originally written for Java, but subsequently ported to many other languages. hamcrest-php is the official PHP port of Hamcrest and essentially follows a literal translation of the original Java API for Hamcrest, with a few Exceptions, mostly down to PHP language barriers:
Unless it would be non-semantic for a matcher to do so, hamcrest-php allows dynamic typing for it's input, in "the PHP way". Exception are where semantics surrounding the type itself would suggest otherwise, such as stringContains() and greaterThan().
Several official matchers have not been ported because they don't make sense or don't apply in PHP:
When most of the collections matchers are finally ported, PHP-specific aliases will probably be created due to a difference in naming conventions between Java's Arrays, Collections, Sets and Maps compared with PHP's Arrays.
** [Unless we consider POPO's (Plain Old PHP Objects) akin to JavaBeans] - The POPO thing is a joke. Java devs coin the term POJO's (Plain Old Java Objects).
Hamcrest matchers are easy to use as:
A tutorial can be found on the Hamcrest site.