vim-patch:9.0.0034: spell tests do not always clear the word list

Problem:    Spell tests do not always clear the word list.
Solution:   Clear the word list in TearDown(). (closes vim/vim#10659)
288ed23e39

src/nvim/testdir/test_spell.vim

@@ -16,6 +16,8 @@ func TearDown()
   call delete('Xtest.latin1.add.spl')
   call delete('Xtest.latin1.spl')
   call delete('Xtest.latin1.sug')
+  " set 'encoding' to clear the word list
+  set encoding=utf-8
 endfunc
 
 func Test_wrap_search()
@@ -726,6 +728,10 @@ func Test_zz_sal_and_addition()
   set spl=Xtest_ca.latin1.spl
   call assert_equal("elequint", FirstSpellWord())
   call assert_equal("elekwint", SecondSpellWord())
+
+  bwipe!
+  set spellfile=
+  set spl&
 endfunc
 
 func Test_spellfile_value()
@@ -809,9 +815,6 @@ func Test_spell_good_word_invalid()
   sil! norm z=
 
   bwipe!
-  " clear the internal word list
-  " set enc=latin1
-  set enc=utf-8
 endfunc
 
 func LoadAffAndDic(aff_contents, dic_contents)

src/nvim/testdir/test_spell_utf8.vim

@@ -13,6 +13,8 @@ func TearDown()
   call delete('Xtest.utf-8.add.spl')
   call delete('Xtest.utf-8.spl')
   call delete('Xtest.utf-8.sug')
+  " set 'encoding' to clear the word list
+  set encoding=utf-8
 endfunc
 
 let g:test_data_aff1 = [
@@ -484,7 +486,6 @@ let g:test_data_aff_sal = [
       \ ]
 
 func LoadAffAndDic(aff_contents, dic_contents)
-  set enc=utf-8
   set spellfile=
   call writefile(a:aff_contents, "Xtest.aff")
   call writefile(a:dic_contents, "Xtest.dic")
@@ -760,6 +761,7 @@ func Test_spell_sal_and_addition()
   call assert_equal("elequint", FirstSpellWord())
   call assert_equal("elekwint", SecondSpellWord())
 
+  bwipe!
   set spellfile=
   set spl&
 endfunc
@@ -803,8 +805,6 @@ func Test_word_index()
   sil norm z=
 
   bwipe!
-  " clear the word list
-  set enc=utf-8
   call delete('Xtmpfile')
 endfunc
 
@@ -817,7 +817,6 @@ func Test_check_empty_line()
   sil! norm P]svc
   norm P]s
 
-  " TODO: should we clear the word list?
   bwipe!
 endfunc