quickfix: fix location list updates (test).

test/functional/core/quickfix_spec.lua

@@ -0,0 +1,31 @@
+local helpers = require('test.functional.helpers')(after_each)
+
+describe('quickfix functionality', function()
+  before_each(function()
+    helpers.clear()
+  end)
+  it('Location list correctly updated when buffer modified', function()
+    helpers.source([[
+        new
+        setl bt=nofile
+        let lines = ['Line 1', 'Line 2', 'Line 3', 'Line 4', 'Line 5']
+        call append(0, lines)
+        new
+        setl bt=nofile
+        call append(0, lines)
+        let qf_item = {
+          \ 'lnum': 4,
+          \ 'text': "This is the error line.",
+          \ }
+        let qf_item['bufnr'] = bufnr('%')
+        call setloclist(0, [qf_item])
+        wincmd p
+        let qf_item['bufnr'] = bufnr('%')
+        call setloclist(0, [qf_item])
+        1del _
+        call append(0, ['New line 1', 'New line 2', 'New line 3'])
+        silent ll
+    ]])
+    helpers.eq({0, 6, 1, 0, 1}, helpers.funcs.getcurpos())
+  end)
+end)