vital: add error handling test on .import and .load

Author: Milly

test/_testdata/vital/testplugin/autoload/vital/__testplugin__/ErrorSelfmodule.vim

@@ -0,0 +1,12 @@
+function! s:_vital_loaded(V) abort
+  call s:Obj._anonymous_func()
+endfunction
+
+let s:Obj = {}
+function! s:Obj._anonymous_func() dict abort
+  call s:_throwFOO()
+endfunction
+
+function! s:_throwFOO() abort
+  throw 'FOO'
+endfunction

test/vital.vimspec

@@ -220,6 +220,14 @@ Describe vital
         Assert Equals(JSON.decode('[1, "ni"]'), [1, "ni"])
       End
 
+      It can handle error stack in s:_vital_loaded(V)
+        Throws /^vital: fail to call \._vital_loaded(): FOO from:\_.*\n
+        \function \S*_vital_loaded(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 1)\n
+        \function \d\+(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 6)\n
+        \function \S*_throwFOO(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 10)/
+        \ :call V.import('ErrorSelfmodule')
+      End
+
       It supports s:_vital_created(V)
         let JSON = V.import('Web.JSON')
         Assert HasKey(JSON, 'true')
@@ -297,6 +305,15 @@ Describe vital
         Assert Equals(V.Web.JSON.decode('[1, "ni"]'), [1, "ni"])
       End
 
+      It can handle error stack in s:_vital_loaded(V)
+        let V = vital#{g:testplugin_name}#new()
+        Throws /^vital: fail to call \._vital_loaded(): FOO from:\_.*\n
+        \function \S*_vital_loaded(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 1)\n
+        \function \d\+(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 6)\n
+        \function \S*_throwFOO(\.\.\.) Line:1 (.*\/ErrorSelfmodule\.vim .* 10)/
+        \ :call V.load('ErrorSelfmodule')
+      End
+
       It supports s:_vital_created(V)
         let V = vital#{g:testplugin_name}#new()
         Assert Equals(V.load('Web.JSON'), V)