patch 8.2.1183: assert_fails() checks the last error message
Problem: assert_fails() checks the last error message.
Solution: Check the first error, it is more relevant. Fix all the tests
that rely on the old behavior.
diff --git a/src/testdir/test_buffer.vim b/src/testdir/test_buffer.vim
index 5981e24..c8f6c5a 100644
--- a/src/testdir/test_buffer.vim
+++ b/src/testdir/test_buffer.vim
@@ -76,7 +76,7 @@
let caught_E90 = 1
endtry
call assert_equal(1, caught_E90)
- call assert_fails('$bunload', 'E515:')
+ call assert_fails('$bunload', 'E90:')
endfunc
" Test for :buffer, :bnext, :bprevious, :brewind, :blast and :bmodified
@@ -278,7 +278,7 @@
call assert_equal(1, &modified)
call assert_equal('', @%)
call feedkeys('y', 'L')
- call assert_fails('confirm b Xfile', 'E37:')
+ call assert_fails('confirm b Xfile', ['', 'E37:'])
call assert_equal(1, &modified)
call assert_equal('', @%)
call feedkeys('n', 'L')