Add primitive manual fuzz testing

test.pl

@@ -2,6 +2,8 @@
 
 use strict;
 
+use File::stat;
+
 assert_produces_correct_output('in.tex', 'correct.txt');
 assert_produces_correct_output('in.tex', 'correct.txt', '-l');
 assert_produces_correct_output('noinclude.tex', 'noinclude-correct.txt', '-n');
@@ -20,6 +22,8 @@
 run_for_input_with_error("test/unterminated-verb.tex");
 run_for_input_with_error("test/unterminated-verb-eol.tex");
 
+fuzz();
+
 print "Tests ok\n";
 
 sub assert_produces_correct_output {
@@ -60,6 +64,22 @@ sub run_for_input_with_error {
 	die "exit code $res" if ($res != 1);
 }
 
+sub fuzz {
+	chdir 'test';
+	my $input = 'in.tex';
+	my $sb = stat($input);
+	for (my $i=0; $i<25; ++$i) {
+		my $bytes = int(rand($sb->size));
+		printf("Fuzz: bytes %5d/%5d of %s. ", $bytes, $sb->size, $input);
+		system("head -c $bytes $input > /tmp/trunc.tex");
+		my $res = system(get_cmd("../delatex /tmp/trunc.tex > /tmp/trunc.log")) >> 8;
+		print "Exit code $res\n";
+		if ($res != 0 && $res != 1) {
+			die;
+		}
+	}
+}
+
 sub execute_cmd {
 	my ($cmd) = @_;
 	my $res = system(get_cmd($cmd));