new file mode 100644
--- /dev/null
+++ b/range_if_range.t
@@ -0,0 +1,122 @@
+#!/usr/bin/perl
+
+# (C) Maxim Dounin
+
+# Tests for range filter module with If-Range header.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http/)->plan(8);
+
+$t->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon         off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        location /t2.html {
+            add_header Last-Modified "";
+        }
+
+        location /t3.html {
+            add_header Last-Modified "Mon, 28 Sep 1970 06:00:00 GMT";
+        }
+    }
+}
+
+EOF
+
+$t->write_file('t1.html',
+	join('', map { sprintf "X%03dXXXXXX", $_ } (0 .. 99)));
+$t->write_file('t2.html',
+	join('', map { sprintf "X%03dXXXXXX", $_ } (0 .. 99)));
+$t->write_file('t3.html',
+	join('', map { sprintf "X%03dXXXXXX", $_ } (0 .. 99)));
+$t->run();
+
+###############################################################################
+
+my $t1;
+
+# If-Range
+
+$t1 = http_get_range('/t1.html', "Range: bytes=0-9\nIf-Range: wrong");
+like($t1, qr/200 OK/, 'if-range wrong');
+like($t1, qr/Last-Modified: /, 'if-range wrong - last modified');
+
+$t1 =~ m/Last-Modified: (.*)/m;
+my $last = $1;
+
+$t1 = http_get_range('/t1.html', "Range: bytes=0-9\nIf-Range: $last");
+like($t1, qr/206/, 'if-range');
+
+# If-Range + add_header Last-Modified ""
+
+$t1 = http_get_range('/t2.html', "Range: bytes=0-9\nIf-Range: wrong");
+
+TODO: {
+local $TODO = 'not yet';
+
+like($t1, qr/200 OK/, 'if-range notime');
+
+}
+
+unlike($t1, qr/Last-Modified: /, 'if-range notime - no last modified');
+
+# If-Range + add_header Last-Modified "Mon, 28 Sep 1970 06:00:00 GMT"
+
+$t1 = http_get_range('/t3.html', "Range: bytes=0-9\nIf-Range: wrong");
+
+TODO: {
+local $TODO = 'not yet';
+
+like($t1, qr/200 OK/, 'if-range time wrong');
+
+}
+
+like($t1, qr/Last-Modified: Mon, 28 Sep 1970 06:00:00 GMT/,
+	'if-range time wrong - last modified');
+
+$t1 = http_get_range('/t3.html',
+	"Range: bytes=0-9\nIf-Range: Mon, 28 Sep 1970 06:00:00 GMT");
+like($t1, qr/206/, 'if-range time');
+
+###############################################################################
+
+sub http_get_range {
+	my ($url, $extra) = @_;
+	return http(<<EOF);
+GET $url HTTP/1.1
+Host: localhost
+Connection: close
+$extra
+
+EOF
+}
+
+###############################################################################