Add: custom variable for minitest spring command (#41)

* Don't hardcode the spring command

Since we may need a different (i.e. non-standard) way of executing the tests, this patch makes it configurable.

* PR feedback

Improved indentation (my fault, apologies).
Improved test to explicitly test new customization variable.

* Fix unit test

minitest.el

@@ -64,11 +64,16 @@
   :type 'list
   :group 'minitest)
 
+(defcustom minitest-spring-command '("spring" "rake" "test")
+  "Spring command for minitest"
+  :type 'list
+  :group 'minitest)
+
 (defun minitest-buffer-name (file-or-dir)
   (concat "*Minitest " file-or-dir "*"))
 
 (defun minitest-test-command ()
-  (let ((command (cond (minitest-use-spring '("spring" "rake" "test"))
+  (let ((command (cond (minitest-use-spring minitest-spring-command)
                        ((minitest-zeus-p) '("zeus" "test"))
                        (minitest-use-rails '("bin/rails" "test"))
                        (t minitest-default-command))))

test/minitest-unit-test.el

@@ -35,7 +35,7 @@
 
 (ert-deftest test-minitest-test-command ()
   (let ((minitest-use-spring t))
-    (should (equal (minitest-test-command) '("spring" "rake" "test"))))
+    (should (equal (minitest-test-command) minitest-spring-command)))
   (let ((minitest-use-docker t)
         (minitest-docker-container "app")
         (minitest-use-rails t))