vim-patch:8.1.0986: rename() is not propertly tested

Problem:    rename() is not propertly tested.
Solution:   Add tests. (Dominique Pelle, closes vim/vim#4061)
ef8c956172

Skip Test_rename_fails() because 'blob' feature is not ported yet.

N/A patches for version.c:

vim-patch:8.2.2678: test for 'autoshelldir' does not reset the option

Problem:    Test for 'autoshelldir' does not reset the option.
Solution:   Reset the option after testing.
82820d9bf1

vim-patch:8.2.2683: build failure without the +eval feature

Problem:    Build failure without the +eval feature.
Solution:   Add #ifdef.
b91d3f857f

src/nvim/testdir/test_alot.vim

@@ -33,6 +33,7 @@ source test_move.vim
 source test_partial.vim
 source test_popup.vim
 source test_put.vim
+source test_rename.vim
 source test_scroll_opt.vim
 source test_sort.vim
 source test_sha256.vim

src/nvim/testdir/test_rename.vim

@@ -0,0 +1,119 @@
+" Test rename()
+
+func Test_rename_file_to_file()
+  call writefile(['foo'], 'Xrename1')
+
+  call assert_equal(0, rename('Xrename1', 'Xrename2'))
+
+  call assert_equal('', glob('Xrename1'))
+  call assert_equal(['foo'], readfile('Xrename2'))
+
+  " When the destination file already exists, it should be overwritten.
+  call writefile(['foo'], 'Xrename1')
+  call writefile(['bar'], 'Xrename2')
+
+  call assert_equal(0, rename('Xrename1', 'Xrename2'))
+  call assert_equal('', glob('Xrename1'))
+  call assert_equal(['foo'], readfile('Xrename2'))
+
+  call delete('Xrename2')
+endfunc
+
+func Test_rename_file_ignore_case()
+  " With 'fileignorecase', renaming file will go through a temp file
+  " when the source and destination file only differ by case.
+  set fileignorecase
+  call writefile(['foo'], 'Xrename')
+
+  call assert_equal(0, rename('Xrename', 'XRENAME'))
+
+  call assert_equal(['foo'], readfile('XRENAME'))
+
+  set fileignorecase&
+  call delete('XRENAME')
+endfunc
+
+func Test_rename_same_file()
+  call writefile(['foo'], 'Xrename')
+
+  " When the source and destination are the same file, nothing
+  " should be done. The source file should not be deleted.
+  call assert_equal(0, rename('Xrename', 'Xrename'))
+  call assert_equal(['foo'], readfile('Xrename'))
+
+  call assert_equal(0, rename('./Xrename', 'Xrename'))
+  call assert_equal(['foo'], readfile('Xrename'))
+
+  call delete('Xrename')
+endfunc
+
+func Test_rename_dir_to_dir()
+  call mkdir('Xrenamedir1')
+  call writefile(['foo'], 'Xrenamedir1/Xrenamefile')
+
+  call assert_equal(0, rename('Xrenamedir1', 'Xrenamedir2'))
+
+  call assert_equal('', glob('Xrenamedir1'))
+  call assert_equal(['foo'], readfile('Xrenamedir2/Xrenamefile'))
+
+  call delete('Xrenamedir2/Xrenamefile')
+  call delete('Xrenamedir2', 'd')
+endfunc
+
+func Test_rename_same_dir()
+  call mkdir('Xrenamedir')
+  call writefile(['foo'], 'Xrenamedir/Xrenamefile')
+
+  call assert_equal(0, rename('Xrenamedir', 'Xrenamedir'))
+
+  call assert_equal(['foo'], readfile('Xrenamedir/Xrenamefile'))
+
+  call delete('Xrenamedir/Xrenamefile')
+  call delete('Xrenamedir', 'd')
+endfunc
+
+func Test_rename_copy()
+  " Check that when original file can't be deleted, rename()
+  " still succeeds but copies the file.
+  call mkdir('Xrenamedir')
+  call writefile(['foo'], 'Xrenamedir/Xrenamefile')
+  call setfperm('Xrenamedir', 'r-xr-xr-x')
+
+  call assert_equal(0, rename('Xrenamedir/Xrenamefile', 'Xrenamefile'))
+
+  if !has('win32')
+    " On Windows, the source file is removed despite
+    " its directory being made not writable.
+    call assert_equal(['foo'], readfile('Xrenamedir/Xrenamefile'))
+  endif
+  call assert_equal(['foo'], readfile('Xrenamefile'))
+
+  call setfperm('Xrenamedir', 'rwxrwxrwx')
+  call delete('Xrenamedir/Xrenamefile')
+  call delete('Xrenamedir', 'd')
+  call delete('Xrenamefile')
+endfunc
+
+func Test_rename_fails()
+  throw 'skipped: TODO: '
+  call writefile(['foo'], 'Xrenamefile')
+
+  " Can't rename into a non-existing directory.
+  call assert_notequal(0, rename('Xrenamefile', 'Xdoesnotexist/Xrenamefile'))
+
+  " Can't rename a non-existing file.
+  call assert_notequal(0, rename('Xdoesnotexist', 'Xrenamefile2'))
+  call assert_equal('', glob('Xrenamefile2'))
+
+  " When rename() fails, the destination file should not be deleted.
+  call assert_notequal(0, rename('Xdoesnotexist', 'Xrenamefile'))
+  call assert_equal(['foo'], readfile('Xrenamefile'))
+
+  " Can't rename to en empty file name.
+  call assert_notequal(0, rename('Xrenamefile', ''))
+
+  call assert_fails('call rename("Xrenamefile", [])', 'E730')
+  call assert_fails('call rename(0z, "Xrenamefile")', 'E976')
+
+  call delete('Xrenamefile')
+endfunc