I am using spacemacs http://spacemacs.org/ You will need to install mocha package and add this config to your .spacemacs config or adjust code to whatever you are using. Basically it switches to a test file and executes tests in that file when you click SPC+m+T

  (require 'projectile)
  (defun atz-exec-if-in-spec-or-switch-and-then-exec (cmd)
    (let ((current-file-name (file-name-nondirectory (buffer-file-name))))
      (if (string-match "spec" current-file-name)
          (funcall cmd)
        (projectile-toggle-between-implementation-and-test)
        (funcall cmd)
        )
      )
    )

  (with-eval-after-load 'js2-mode
    (evil-leader/set-key "mT"
      '(lambda()
         (interactive)
         (atz-exec-if-in-spec-or-switch-and-then-exec 'mocha-test-file)
         )
      )
    )