Extract method to parse 'def' and 'async'

There's 2 small fixes:

- Extends regex search for the line end with a comment.
- Update insert position for the line end with a comment.

Add test cases for above cases.

Author: Le Tien Tai

autoload/pydocstring.vim

@@ -53,8 +53,19 @@ function! s:parseClass(line)
   return parse
 endfunction
 
+function! s:parseFunc(type, line)
+  let header = substitute(a:line, '\s\|(.*\|:', '', 'g')
+
+  let argsStr = substitute(a:line, '\s\|.*(\|).*', '', 'g')
+  let args = split(argsStr, ',')
+
+  let parse = {'type': a:type, 'header': header, 'args': args}
+  return parse
+endfunction
+
 function! s:parse(line)
   let str = substitute(a:line, '\\', '', 'g')
+  let str = substitute(a:line, '#.*$', '', 'g')
   let type = ''
 
   if str =~ s:regexs['class']
@@ -71,18 +82,8 @@ function! s:parse(line)
   else
     return 0
   endif
-  let str = substitute(str, '\s\|):\|)\s:', '', 'g')
-
-  let strs = split(str, '(')
-  let header = strs[0]
-  let args = []
-  if len(strs) > 1
-    let args = split(strs[1], ',')
-  end
 
-  let parse = {'type': type, 'header': header, 'args': args}
-
-  return parse
+  return s:parseFunc(type, str)
 endfunction
 
 " Vim Script does not support lambda function...
@@ -172,7 +173,7 @@ function! pydocstring#insert()
   let indent = matchstr(line, '^\(\s*\)')
 
   let startpos = line('.')
-  let insertpos = search('\:\+$')
+  let insertpos = search('\:\(\s*#.*\)*$')
   let lines = join(getline(startpos, insertpos))
 
   let docstring = s:parse(lines)

test/basic.vader

@@ -45,6 +45,23 @@ Expect python:
         """
         pass
 
+Given python (def foo with 2 params and a comment block):
+    def foo(arg1, arg2): # Something fun (just, for, test)
+        pass
+
+Execute:
+    Pydocstring
+
+Expect python:
+    def foo(arg1, arg2): # Something fun (just, for, test)
+        """foo
+
+        :param arg1:
+        :param arg2:
+        """
+        pass
+
+
 Given python (def foo with variadic params):
     def foo(*arg):
         pass