+my $date_time = Sip::timestamp();
+like( $date_time, qr/^\d{8} \d{6}$/, 'Timestamp format no param');
+
+my $t = time();
+
+$date_time = Sip::timestamp($t);
+like( $date_time, qr/^\d{8} \d{6}$/, 'Timestamp format secs');
+
+$date_time = Sip::timestamp('2011-01-12');
+ok( $date_time eq '20110112 235900', 'Timestamp iso date string');
+
+my $myChecksum = Sip::Checksum::checksum("12345");
+my $checker = 65281;
+my $stringChecksum = Sip::Checksum::checksum("teststring");
+my $stringChecker = 64425;
+
+is( $myChecksum, $checker, "Checksum: $myChecksum matches expected output");
+is( $stringChecksum, $stringChecker, "Checksum: $stringChecksum matches expected output");
+
+my $testdata = "abcdAZ";
+my $something = Sip::Checksum::checksum($testdata);
+
+$something = sprintf("%4X", $something);
+ok( Sip::Checksum::verify_cksum($testdata.$something), "Checksum: $something is valid.");
+
+my $invalidTest = Sip::Checksum::verify_cksum("1234567");
+is($invalidTest, 0, "Checksum: 1234567 is invalid as expected");