Tests for tests spun off and included

Now it checks not only valid Pod6, but also valid syntax.

This is actually a workaround for #1951. It was a Rakudo error having
to do with the setting up of a compunit, which is created when the
file is interpreted. It happened, when it did, by the end of the
tests. It became less frequent when the tests were split in two
batches, but it still happens from time to time. Spinning off these
tests should solve it. Besides, testing test files for valid POD6 is
not so critical, so it might be a good idea to move this new one to an
author test.

Anyway, closes #1951. If it keeps happening, we'll try to find another
workaround.

Author: JJ

t/02-pod-valid.t

@@ -9,19 +9,17 @@ use Test-Files;
 
 =begin overview
 
-Ensure any text that isn't a code example is valid Pod 6.
+Ensure any text that isn't a code example is valid C<Pod 6>.
 
 =end overview
 
 my $max-jobs = %*ENV<TEST_THREADS> // 2;
 
 my @files-pod = Test-Files.files.grep({$_.ends-with: '.pod6'});
-my @files-t = Test-Files.files.grep({$_.ends-with: '.t'});
-plan +@files-t + +@files-pod;
+plan +@files-pod;
 
 my %data;
 test-files( @files-pod ); #Splits in two batches to avoid some errors.
-test-files( @files-t );
 
 sub test-it($job) {
     my $file = $job.command[*-1];

t/02-tests-valid.t

@@ -0,0 +1,54 @@
+#!/usr/bin/env perl6
+
+use v6;
+use lib 'lib';
+use Test;
+BEGIN plan :skip-all<Test applicable to git checkout only> unless '.git'.IO.e;
+
+use Test-Files;
+
+=begin overview
+
+Ensure any test file, including author tests, have clean syntax and POD
+
+=end overview
+
+my $max-jobs = %*ENV<TEST_THREADS> // 2;
+
+my @files-t = Test-Files.files.grep({$_.ends-with: '.t'});
+plan +@files-t;
+
+my %data;
+test-files( @files-t );
+
+sub test-it($job) {
+    my $file = $job.command[*-1];
+    ok !$job.exitcode && !%data{$file}, "$file POD6 and syntax check out"
+}
+
+sub test-files( @files ) {
+    my @jobs;
+    %data{@files} = 0 xx @files;
+    for @files -> $file {
+        my $p =  Proc::Async.new($*EXECUTABLE-NAME, '--c', $file);
+        $p.stdout.tap: {;};
+        $p.stderr.tap: {
+            %*ENV<P6_DOC_TEST_VERBOSE>
+            and diag qq:to/EOF/;
+There's been this error in file: $file
+$_
+EOF
+            %data{$file} = 1;
+        }
+        push @jobs: $p.start;
+        if +@jobs > $max-jobs {
+            test-it(await @jobs.shift);
+        }
+    }
+
+    # In case there's something left to run.
+    for @jobs.map: {await $_} -> $r { test-it($r) }
+}
+
+
+# vim: expandtab shiftwidth=4 ft=perl6