Added test cases for sorting and marking as done.

test/tc_sort_project.vim

@@ -0,0 +1,20 @@
+let s:here = expand('<sfile>:p:h')
+let s:tc = unittest#testcase#new('Sort Project', 
+      \ { 'data': s:here . '/tc_sort_project.todo.txt' })
+
+let s:LEADER = mapleader
+
+let s:SORTED_TASKS = [
+      \ '(B) Review key questions. +benchmarking',
+      \ '(B) Linear regression Rnet=Qh+Qle. +cons_emp_model',
+      \ '(A) simple model first +cons_emp_model',
+      \ ]
+
+function! s:tc.test_sort_by_project()
+  execute 'normal ' . s:LEADER . 's+'
+  execute 'normal ggO# lorem_ipsum'
+  execute 'normal Go# end_lorem_ipsum'
+  call self.assert_equal(s:SORTED_TASKS, self.data.get('lorem_ipsum'))
+endfunction
+
+unlet s:tc