Refactor and extract functions in alchemist-project

I extracted a bunch of functions from alchemist-project to
alchemist-utils and added tests for them.

alchemist-project.el

@@ -134,21 +134,6 @@ Point is left in a convenient location."
   (goto-char (point-min))
   (beginning-of-line 3))
 
-(defun alchemist-project--underscore-to-camelcase (string)
-  "Convert an underscore_string to a CamelCase string."
-  (mapconcat 'capitalize (split-string string "_") ""))
-
-(defun alchemist-project--path-to-module-name (path)
-  "Convert a `path' like my_lib/foo.ex to a module name like MyLib.Foo."
-  (let* ((path (split-string path "/"))
-         (path (mapcar (lambda (el) (replace-regexp-in-string "\.ex$" "" el)) path)))
-    (mapconcat 'alchemist-project--underscore-to-camelcase path ".")))
-
-(defun alchemist-project--maybe-add-file-extension-to-path (path)
-  (if (string-match-p "\.ex$" path)
-      path
-    (concat abs-path ".ex")))
-
 (defun alchemist-project-run-tests-for-current-file ()
   "Run the tests related to the current file."
   (interactive)
@@ -164,14 +149,14 @@ The newly created buffer is filled with a module definition based on the file na
         (message "You're not in a Mix project")
       (let* ((lib-path (concat root "lib/"))
              (abs-path (read-file-name "New file in lib/: " lib-path))
-             (abs-path (alchemist-project--maybe-add-file-extension-to-path abs-path))
+             (abs-path (alchemist-utils--add-ext-to-path-if-not-present abs-path ".ex"))
              (relative-path (file-relative-name abs-path lib-path)))
         (if (file-readable-p abs-path)
             (message "%s already exists" relative-path)
           (make-directory (file-name-directory abs-path) t)
           (find-file abs-path)
           (insert (concat "defmodule "
-                          (alchemist-project--path-to-module-name relative-path)
+                          (alchemist-utils--path-to-module-name relative-path)
                           " do\n"
                           "  \n"
                           "end\n"))

alchemist-utils.el

@@ -107,6 +107,29 @@ It walks the directory tree until it finds a elixir project root indicator."
   (let* ((modules (mapconcat #'identity modules ",")))
     (format "[%s]" modules)))
 
+(defun alchemist-utils--snakecase-to-camelcase (str)
+  "Convert a snake_case string `STR' to a CamelCase string.
+
+This function is useful for converting file names like my_module to Elixir
+module names (MyModule)."
+  (mapconcat 'capitalize (split-string str "_") ""))
+
+(defun alchemist-utils--add-ext-to-path-if-not-present (path ext)
+  "Add `EXT' to `PATH' if `PATH' doesn't already ends with `EXT'."
+  (if (string-suffix-p ext path)
+      path
+    (concat path ext)))
+
+(defun alchemist-utils--path-to-module-name (path)
+  "Convert `PATH' to its Elixir module name equivalent.
+
+For example, convert 'my_app/my_module.ex' to 'MyApp.MyModule'."
+  (let* ((path (file-name-sans-extension path))
+         (path (split-string path "/"))
+         (path (remove-if (lambda (str) (equal str "")) path)))
+    (mapconcat #'alchemist-utils--snakecase-to-camelcase path ".")))
+
+
 (provide 'alchemist-utils)
 
 ;;; alchemist-utils.el ends here

test/alchemist-utils-test.el

@@ -89,6 +89,19 @@ a text")))
                   (list "Ek" "Behaviour" "Plug.Conn"))))
   (should (equal "[]" (alchemist-utils--prepare-modules-for-elixir '("")))))
 
+(ert-deftest test-utils/snakecase-to-camelcase ()
+  (should (equal "MyCustomModule" (alchemist-utils--snakecase-to-camelcase "my_custom_module")))
+  (should (equal "Foo" (alchemist-utils--snakecase-to-camelcase "foo"))))
+
+(ert-deftest test-utils/add-ext-to-path-if-not-present ()
+  (should (equal "foo.ex" (alchemist-utils--add-ext-to-path-if-not-present "foo.ex" ".ex")))
+  (should (equal "foo.ex" (alchemist-utils--add-ext-to-path-if-not-present "foo" ".ex")))
+  (should (equal "foo.ex.exs" (alchemist-utils--add-ext-to-path-if-not-present "foo.ex" ".exs"))))
+
+(ert-deftest test-utils/path-to-module-name ()
+  (should (equal "MyApp.MyModule" (alchemist-utils--path-to-module-name "my_app/my_module.ex")))
+  (should (equal "Foo.Bar" (alchemist-utils--path-to-module-name "/foo/bar")))
+  (should (equal "Foo" (alchemist-utils--path-to-module-name "//foo//"))))
 
 (provide 'alchemist-utils-tests)