expect with expressions-as-predicate don't always work as expected

[seancorfield]

@camsaul highlighted this difference from "classic" Expectations:

seanc@DESKTOP-30ICA76:~/clojure$ clj -Sdeps '{:deps {expectations/expectations {:mvn/version "RELEASE"}}}'
Clojure 1.10.3
user=> (use 'expectations)
nil
user=> (expect (re-pattern "\\d+") "1000")
#'user/expect1608036982
user=>

Ran 1 tests containing 1 assertions in 3 msecs
0 failures, 0 errors.
seanc@DESKTOP-30ICA76:~/clojure$ clj -Sdeps '{:deps {com.github.seancorfield/expectations {:mvn/version "RELEASE"}}}'
Clojure 1.10.3
user=> (use 'expectations.clojure.test)
nil
user=> (expect (re-pattern "\\d+") "1000")

FAIL in () (NO_SOURCE_FILE:1)
"1000"

expected: (=? (re-pattern "\\d+") "1000")
  actual: (not (=? #"\d+" "1000"))
false
user=>

This is not an intentional change but likely happens because e.c.t tries to determine, at macro expansion time, how to run the predicate test under the hood.

[seancorfield]

Looking at the code, I think this is the only omission in the logic (regex patterns) because ?= already implemented the other checks (spec, function, value). The regex logic in expect only worked with literal regex and essentially should only have been an optimization.