init.el

(defun jim/cider-test-is-test-ns (ns)
  (let ((suffix "-test")) 
    (string-match (rx-to-string `(: ,suffix eos) t) ns)))

(defun jim/cider-test-impl-ns-fn (ns)
  (when ns
    (let ((suffix "-test"))
      (if (string-match (rx-to-string `(: ,suffix eos) t) ns)
          (s-replace suffix "" ns)
        ns))))

(defun jim/cider-test-jump-around ()
  (interactive)
  (let ((ns (cider-current-ns)))
    (switch-to-buffer
     (cider-find-buffer
      (if (jim/cider-test-is-test-ns ns)
          (jim/cider-test-impl-ns-fn ns)
        (cider-test-default-test-ns-fn ns))))))

(defun jim/clojure-keybinds ()
  (interactive)
  (define-key clojure-mode-map (kbd "C-c C-e") 'cider-pprint-eval-last-sexp)
  (define-key cider-mode-map (kbd "C-c C-t") 'jim/cider-test-jump-around)
  (define-key cider-mode-map (kbd "C-c M-,") 'cider-test-run-tests))

(add-hook 'clojure-mode-hook 'jim/clojure-keybinds)