Fix macos eof (#349)

* Test .eof on TTY handles works right

RT#132349: https://rt.perl.org/Ticket/Display.html?id=132349

* Fix test's failure mode

On failure, it diag()s the received output, but diag returns True,
causing the failed test to succeed

* Reword proc launch

We can't .Bool a Proc as that'll cause its `await`ion before
we sent stuff to STDIN

S16-io/eof.t

@@ -1,10 +1,15 @@
 use v6;
+use lib <t/spec/packages/>;
 use Test;
-plan 2;
+use Test::Util;
+
+plan 3;
 
 sub nonce () { return (".{$*PID}." ~ 1000.rand.Int) }
 
 my $tmpfile = "eof-test-" ~ nonce();
+END unlink $tmpfile;
+
 {
   my $fh = open($tmpfile, :w) or die qq/Failed to open "$tmpfile": $!/;
   $fh.print: "EOF_TESTING\n\n";
@@ -39,6 +44,15 @@ my $tmpfile = "eof-test-" ~ nonce();
   }
 }
 
-END { unlink $tmpfile }
+# RT # 132349
+run-with-tty ｢with $*IN { .eof.say; .slurp.say; .eof.say }｣, :in<meow>,
+    # Here we use .ends-width because (currently) there's some sort of
+    # bug with Proc or something where sent STDIN ends up on our STDOUT.
+    # Extra "\n" after `meow` is 'cause run-as-tty sends extra new line,
+    # 'cause MacOS's `script` really wants it or something
+    :out{ .ends-with: "False\nmeow\n\nTrue\n" or do {
+        diag "Got STDOUT: {.perl}";
+        False;
+    }}, '.eof on TTY STDIN works right';
 
 # vim: ft=perl6

packages/Test/Util.pm

@@ -307,18 +307,14 @@ sub run-with-tty (
 
     subtest $desc => {
         $path.IO.spurt: $code;
-        if shell :in, :out, :err, $script -> $_ {
+        given shell :in, :out, :err, $script {
             plan 3;
             # on MacOS, `script` really wants the ending newline...
             .in.spurt: "$in\n", :close;
             cmp-ok .out.slurp(:close), '~~', $out,    'STDOUT';
             cmp-ok .err.slurp(:close), '~~', $err,    'STDERR';
             cmp-ok .exitcode,  '~~', $status, 'exit code';
         }
-        else {
-            plan 1;
-            flunk "Failed to run command; exitcode: $^proc.exitcode()";
-        }
     }
 }