vim-patch:partial:8.2.0418: code in eval.c not sufficiently covered by tests

Problem:    Code in eval.c not sufficiently covered by tests.
Solution:   Add more tests. (Yegappan Lakshmanan, closes vim/vim#5815)
8b63313510

Only port test_expr.vim and the first hunk of test_cmdline.vim.
Add missing test from patch 7.4.1755.
Cherry-pick test_expr.vim change from patch 8.2.2060.

src/nvim/testdir/test_cmdline.vim

@@ -349,35 +349,6 @@ func Test_highlight_completion()
   call assert_equal([], getcompletion('A', 'highlight'))
 endfunc
 
-func Test_expr_completion()
-  if !has('cmdline_compl')
-    return
-  endif
-  for cmd in [
-	\ 'let a = ',
-	\ 'const a = ',
-	\ 'if',
-	\ 'elseif',
-	\ 'while',
-	\ 'for',
-	\ 'echo',
-	\ 'echon',
-	\ 'execute',
-	\ 'echomsg',
-	\ 'echoerr',
-	\ 'call',
-	\ 'return',
-	\ 'cexpr',
-	\ 'caddexpr',
-	\ 'cgetexpr',
-	\ 'lexpr',
-	\ 'laddexpr',
-	\ 'lgetexpr']
-    call feedkeys(":" . cmd . " getl\<Tab>\<Home>\"\<CR>", 'xt')
-    call assert_equal('"' . cmd . ' getline(', getreg(':'))
-  endfor
-endfunc
-
 func Test_getcompletion()
   if !has('cmdline_compl')
     return

src/nvim/testdir/test_expr.vim

@@ -1,5 +1,7 @@
 " Tests for expressions.
 
+source check.vim
+
 func Test_equal()
   let base = {}
   func base.method()
@@ -76,6 +78,17 @@ func Test_strcharpart()
   call assert_equal('', strcharpart('axb', -2, 2))
 
   call assert_equal('a', strcharpart('axb', -1, 2))
+
+  call assert_equal('edit', "editor"[-10:3])
+endfunc
+
+func Test_getreg_empty_list()
+  call assert_equal('', getreg('x'))
+  call assert_equal([], getreg('x', 1, 1))
+  let x = getreg('x', 1, 1)
+  let y = x
+  call add(x, 'foo')
+  call assert_equal(['foo'], y)
 endfunc
 
 func Test_loop_over_null_list()
@@ -529,6 +542,7 @@ func Test_function_with_funcref()
 
   call assert_fails("call function('foo()')", 'E475:')
   call assert_fails("call function('foo()')", 'foo()')
+  call assert_fails("function('')", 'E129:')
 endfunc
 
 func Test_funcref()
@@ -587,3 +601,93 @@ func Test_eval_after_if()
   if 0 | eval SetVal('a') | endif | call SetVal('b')
   call assert_equal('b', s:val)
 endfunc
+
+" Test for command-line completion of expressions
+func Test_expr_completion()
+  CheckFeature cmdline_compl
+  for cmd in [
+	\ 'let a = ',
+	\ 'const a = ',
+	\ 'if',
+	\ 'elseif',
+	\ 'while',
+	\ 'for',
+	\ 'echo',
+	\ 'echon',
+	\ 'execute',
+	\ 'echomsg',
+	\ 'echoerr',
+	\ 'call',
+	\ 'return',
+	\ 'cexpr',
+	\ 'caddexpr',
+	\ 'cgetexpr',
+	\ 'lexpr',
+	\ 'laddexpr',
+	\ 'lgetexpr']
+    call feedkeys(":" . cmd . " getl\<Tab>\<Home>\"\<CR>", 'xt')
+    call assert_equal('"' . cmd . ' getline(', getreg(':'))
+  endfor
+
+  " completion for the expression register
+  call feedkeys(":\"\<C-R>=float2\t\"\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"float2nr("', @=)
+
+  " completion for window local variables
+  let w:wvar1 = 10
+  let w:wvar2 = 10
+  call feedkeys(":echo w:wvar\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo w:wvar1 w:wvar2', @:)
+  unlet w:wvar1 w:wvar2
+
+  " completion for tab local variables
+  let t:tvar1 = 10
+  let t:tvar2 = 10
+  call feedkeys(":echo t:tvar\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo t:tvar1 t:tvar2', @:)
+  unlet t:tvar1 t:tvar2
+
+  " completion for variables
+  let g:tvar1 = 1
+  let g:tvar2 = 2
+  call feedkeys(":let g:tv\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"let g:tvar1 g:tvar2', @:)
+  " completion for variables after a ||
+  call feedkeys(":echo 1 || g:tv\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo 1 || g:tvar1 g:tvar2', @:)
+
+  " completion for options
+  call feedkeys(":echo &compat\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo &compatible', @:)
+  call feedkeys(":echo 1 && &compat\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo 1 && &compatible', @:)
+  call feedkeys(":echo &g:equala\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal('"echo &g:equalalways', @:)
+
+  " completion for string
+  call feedkeys(":echo \"Hello\\ World\"\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal("\"echo \"Hello\\ World\"\<C-A>", @:)
+  call feedkeys(":echo 'Hello World'\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal("\"echo 'Hello World'\<C-A>", @:)
+
+  " completion for command after a |
+  call feedkeys(":echo 'Hello' | cwin\<C-A>\<C-B>\"\<CR>", 'xt')
+  call assert_equal("\"echo 'Hello' | cwindow", @:)
+
+  " completion for environment variable
+  let $X_VIM_TEST_COMPLETE_ENV = 'foo'
+  call feedkeys(":let $X_VIM_TEST_COMPLETE_E\<C-A>\<C-B>\"\<CR>", 'tx')
+  call assert_match('"let $X_VIM_TEST_COMPLETE_ENV', @:)
+  unlet $X_VIM_TEST_COMPLETE_ENV
+endfunc
+
+" Test for errors in expression evaluation
+func Test_expr_eval_error()
+  call assert_fails("let i = 'abc' . []", 'E730:')
+  call assert_fails("let l = [] + 10", 'E745:')
+  call assert_fails("let v = 10 + []", 'E745:')
+  call assert_fails("let v = 10 / []", 'E745:')
+  call assert_fails("let v = -{}", 'E728:')
+endfunc
+
+" vim: shiftwidth=2 sts=2 expandtab