Add concurrency testing from three processes.

diff --git a/t/02-IndexData-Utils-PersistentCounter.t b/t/02-IndexData-Utils-PersistentCounter.t
index a7752d6..aa05060 100644 (file)
--- a/t/02-IndexData-Utils-PersistentCounter.t
+++ b/t/02-IndexData-Utils-PersistentCounter.t
@@ -1,7 +1,7 @@
 use strict;
 use warnings;
 
-use Test::More tests => 16;
+use Test::More tests => 17;
 BEGIN { use_ok('IndexData::Utils::PersistentCounter') };
 
 my $file = "/tmp/id-u-pc-$$";
@@ -21,7 +21,27 @@ foreach my $i (1..5) {
     ok($n == $i, "n has correct value $i");
 }
 
-### should test access from multiple processes
+# Three processes making five accesses each
+for (my $i = 0; $i < 3; $i ++) {
+    my $pid = fork();
+    if ($pid == 0) {
+       # child
+       foreach my $j (1..5) {
+           my $n = $counter->next();
+           print "# child ", $i+1, ", access ", $j+1, ": value is $n\n";
+       }
+       exit 0;
+    } else {
+       print "# process $pid started\n";
+    }
+}
+
+while ((my $pid = wait()) > 0) {
+    print "# process $pid completed\n";
+}
+
+my $n = $counter->next();
+ok($n == 20, "n == 20 after 20 accesses (n=$n)");
 
 my $ok = $counter->delete();
 ok($ok, "deleted counter file");