link to complement

Author: ara4n

README.rst

@@ -8,6 +8,12 @@ regular HTTP interaction much as any other Matrix client would do. It can
 output test results either to an interactive terminal, or as a TAP-style test
 report, for continuous-integration test harnesses such as Jenkins.
 
+SyTest is written in Perl, and is the original integration testing system for
+Matrix.  New tests tend to be written in Complement_, a Go-based integration
+testing system.
+
+.. _Complement: https://github.com/matrix-org/complement
+
 Installing
 ----------