patch 8.2.0766: display error when using 'number' and 'breakindent'

Problem:    Display error when using 'number' and 'breakindent'.
Solution:   Adjust extra spaces in the first row. (Ken Takata, closes #6089,
            closes #5986)
diff --git a/src/testdir/test_breakindent.vim b/src/testdir/test_breakindent.vim
index aea0572..30c44f4 100644
--- a/src/testdir/test_breakindent.vim
+++ b/src/testdir/test_breakindent.vim
@@ -696,4 +696,51 @@
   call s:close_windows('set breakindent& briopt& sbr&')
 endfunc
 
+func Test_breakindent20_cpo_n_nextpage()
+  let s:input = ""
+  call s:test_windows('setl breakindent briopt=min:14 cpo+=n number')
+  call setline(1, repeat('a', 200))
+  norm! 1gg
+  redraw!
+  let lines = s:screen_lines(1, 20)
+  let expect = [
+	\ "  1 aaaaaaaaaaaaaaaa",
+	\ "    aaaaaaaaaaaaaaaa",
+	\ "    aaaaaaaaaaaaaaaa",
+	\ ]
+  call s:compare_lines(expect, lines)
+  " Scroll down one screen line
+  setl scrolloff=5
+  norm! 5gj
+  redraw!
+  let lines = s:screen_lines(1, 20)
+  let expect = [
+	\ "--1 aaaaaaaaaaaaaaaa",
+	\ "    aaaaaaaaaaaaaaaa",
+	\ "    aaaaaaaaaaaaaaaa",
+	\ ]
+  call s:compare_lines(expect, lines)
+
+  setl briopt+=shift:2
+  norm! 1gg
+  let lines = s:screen_lines(1, 20)
+  let expect = [
+	\ "  1 aaaaaaaaaaaaaaaa",
+	\ "      aaaaaaaaaaaaaa",
+	\ "      aaaaaaaaaaaaaa",
+	\ ]
+  call s:compare_lines(expect, lines)
+  " Scroll down one screen line
+  norm! 5gj
+  let lines = s:screen_lines(1, 20)
+  let expect = [
+	\ "--1   aaaaaaaaaaaaaa",
+	\ "      aaaaaaaaaaaaaa",
+	\ "      aaaaaaaaaaaaaa",
+	\ ]
+  call s:compare_lines(expect, lines)
+
+  call s:close_windows('set breakindent& briopt& cpo& number&')
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab