When the CLJ REPL and Shadow are sharing JVM, RCF tests are enabled at the CLJ repl and Shadow needs to disable JVM RCF tests during incremental builds because :require-macros in a CLJS file will cause the CLJ files to load, running tests if enabled.
https://shadow-cljs.github.io/docs/UsersGuide.html#compile-stages
(defn rcf-shadow-hook
{:shadow.build/stage #{:configure :flush}}
[build-state & args]
(case (:shadow.build/stage build-state)
:configure (enable! false)
:flush (enable!))
build-state)