Existence of hamcrest_assertions is usefull, but requires addition of an extra crate. It would be beneficial if user could write test_case(args => is ...) without extra work.

For first release, for all assertions provided by hamcrest2 lib we should either cover it with our own syntax or mention replacement/why it's not implemented.

Later we'll be able to expand functionality of is|it on our own.

General matchers

• eq - already covered via arg => value is equal_to X
• not eq
• (not) lt is less_than X
• (not) leq is less_or_equal_than X
• (not) gt is greater_than X
• (not) geq is greater_or_equal_than X
• (not) type_of - do we need that?
• Add it (not) matches_regex ... #80

Numerical matchers

• (not) close_to is almost_equal_to X

Filesystem matchers

• (not) path_exists is existing_path
• (not) file_exists is file
• (not) dir_exists is dir

Option and Result

• has - matches Ok(5) can be used
• negated has - matches Ok(v) if v != 5
• (not) ok - matches Ok(_) & matches Err(_)
• (not) err - same
• (not) some - same
• (not) none - same

Collection matchers

• (not) contains it contains X
• (not) contains_exactly - matches vec![1, 2, 3] & matches [1, 2, 3]
• (not) contains_in_order it contains_in_order [X, Y, Z]
• Add is (not) len ... #81
• Add is (not) empty #82

Compound matchers

• (not) all
• (not) any

Misc

• is(bool) - supported via arg => value
• anything - useless in test_case context