tests: Migrate legacy test sort

src/nvim/testdir/test_alot.vim

@@ -1,4 +1,3 @@
 " A series of tests that can run in one Vim invocation.
 " This makes testing go faster, since Vim doesn't need to restart.
 
-source test_sort.vim

src/nvim/testdir/test_sort.vim

@@ -1,23 +0,0 @@
-" Test sort()
-
-func Test_sort_strings()
-  " numbers compared as strings
-  call assert_equal([1, 2, 3], sort([3, 2, 1]))
-  call assert_equal([13, 28, 3], sort([3, 28, 13]))
-endfunc
-
-func Test_sort_numeric()
-  call assert_equal([1, 2, 3], sort([3, 2, 1], 'n'))
-  call assert_equal([3, 13, 28], sort([13, 28, 3], 'n'))
-  " strings are not sorted
-  call assert_equal(['13', '28', '3'], sort(['13', '28', '3'], 'n'))
-endfunc
-
-func Test_sort_numbers()
-  call assert_equal([3, 13, 28], sort([13, 28, 3], 'N'))
-  call assert_equal(['3', '13', '28'], sort(['13', '28', '3'], 'N'))
-endfunc
-
-func Test_sort_float()
-  call assert_equal([0.28, 3, 13.5], sort([13.5, 0.28, 3], 'f'))
-endfunc

test/functional/legacy/function_sort_spec.lua

@@ -0,0 +1,29 @@
+local helpers = require('test.functional.helpers')
+local clear = helpers.clear
+local eq = helpers.eq
+local eval = helpers.eval
+
+describe('sort', function()
+  before_each(clear)
+
+  it('numbers compared as strings', function()
+    eq({1, 2, 3}, eval('sort([3, 2, 1])'))
+    eq({13, 28, 3}, eval('sort([3, 28, 13])'))
+  end)
+
+  it('numbers compared as numeric', function()
+    eq({1, 2, 3}, eval("sort([3, 2, 1], 'n')"))
+    eq({3, 13, 28}, eval("sort([3, 28, 13], 'n')"))
+    -- Strings are not sorted.
+    eq({'13', '28', '3'}, eval("sort(['13', '28', '3'], 'n')"))
+  end)
+
+  it('numbers compared as numbers', function()
+    eq({3, 13, 28}, eval("sort([13, 28, 3], 'N')"))
+    eq({'3', '13', '28'}, eval("sort(['13', '28', '3'], 'N')"))
+  end)
+
+  it('numbers compared as float', function()
+    eq({0.28, 3, 13.5}, eval("sort([13.5, 0.28, 3], 'f')"))
+  end)
+end)