Make like() and unlike() in t/test.pl refuse non-qr// arguments

As I noted in v5.21.1-12-g826af13 we have subtle bugs in the test suite
because you can do e.g. like($@, '') now which'll be a passing test even
when we have an error, because $@ =~ // will be true.

I'm just changing t/test.pl to not accept non-Regexp arguments, and
fixing up a bunch of test failures that resulted from that. There might
still be more of these in tests that I'm just not running, I've also
changed some of these from $str =~ /foo/ to $str eq 'foo'
(i.e. s/like/is/) in cases where that appeared to work, but it might
break some systems.

Let's just find that out via the smokers.

1 files changed, 8 insertions, 0 deletions

diff --git a/t/test.pl b/t/test.pl
index 2b566230a6..342cfdc340 100644
--- a/t/test.pl
+++ b/t/test.pl
@@ -420,6 +420,14 @@ sub unlike ($$@) { like_yn (1,@_) }; # 1 for un-
 
 sub like_yn ($$$@) {
     my ($flip, undef, $expected, $name, @mess) = @_;
+
+    # We just accept like(..., qr/.../), not like(..., '...'), and
+    # definitely not like(..., '/.../') like
+    # Test::Builder::maybe_regex() does.
+    unless (re::is_regexp($expected)) {
+	die "PANIC: The value '$expected' isn't a regexp. The like() function needs a qr// pattern, not a string";
+    }
+
     my $pass;
     $pass = $_[1] =~ /$expected/ if !$flip;
     $pass = $_[1] !~ /$expected/ if $flip;