Add compatibility with matcher-combinators

Currently when running a test through cider, any failures in a
`(is (match? ,,,))` clause will be silently ignores.

This detects mismatch messages and treats them as failure messages. Where there
is a mismatch the user will see a {:expected x :actual y} in the test output.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### New features
+
+* [#546](https://github.com/clojure-emacs/cider-nrepl/pull/546): Added support for matcher-combinators to the test middleware.
+
 ## 0.18.0 (2018-08-06)
 
 ### New features

src/cider/nrepl/middleware/test.clj

@@ -171,6 +171,12 @@
   [m]
   (report-shrinking m))
 
+(defmethod report :matcher-combinators/mismatch
+  [m]
+  (report-final-status (assoc m
+                              :type :fail
+                              :actual (:markup m))))
+
 (defn report-fixture-error
   "Delegate reporting for test fixture errors to the `report` function. This
   finds the erring test fixture in the stacktrace and binds it as the current