https://clojureverse.org/t/a-gotcha-test-core-thrown/5595/1 Clojure is generally such a pristine and sensible language, it took me some debugging time to find out why this was failing: (is (let [proctorless-rmap {:tester (:id tester) :test (:id this-test)}] (thrown? Exception (xreg/register-for-exam proctorless-rmap)) "no proctor should fail")) ;; Unable to resolve symbol: thrown? in this context Trying to solve this at the repl, I was stumped for quite a while by why I couldn’t locate the thrown? function with C-c C-.