diff --git a/README.md b/README.md
index 6afab9c63..e877a123a 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,8 @@ MKVToolNix 9.7.1
   5. Notes for compilation on (Open)Solaris
   6. Unit tests
 3. Reporting bugs
-4. Included libraries and their licenses
+4. Test suite and continuous integration tests
+5. Included libraries and their licenses
   1. avilib
   2. Boost's utf8_codecvt_facet
   3. libEBML
@@ -239,11 +240,44 @@ them somewhere and post a link in the issue. You can also upload them
 to my FTP server. Details on how to connect can be found in the
 [MKVToolNix FAQ](https://github.com/mbunkus/mkvtoolnix/wiki/FTP-server).
 
-# 4. Included libraries and their licenses
+# 4. Test suite and continuous integration tests
+
+MKVToolNix contains a lot of test cases in order to detect regressions
+before they're released. Regressions include both compilation issues
+as well as changes from expected program behavior.
+
+As mentioned in section 2.6., MKVToolNix comes with a set of unit
+tests based on the Google Test library in the `tests/unit`
+sub-directory that you can run yourself. These cover only a small
+amount of code, and any effort to extend them would be most welcome.
+
+A second test suite exists that targets the program behavior, e.g. the
+output generated by mkvmerge when specific options are used with
+specific input files. These are the test cases in the `tests`
+directory itself. Unfortunately the files they run on often contain
+copyrighted material that I cannot distribute. Therefore you cannot
+run them yourself.
+
+A third pillar of the testing effort is the
+[continuous integration tests](https://mkvtoolnix.download/buildbot/grid)
+run on a Buildbot instance. These are run automatically for each
+commit made to the git repository. The tests include:
+
+  * building of all the packages for Linux distributions that I
+    normally provide for download myself in both 32bit and 64bit
+    variants
+  * building of the Windows installer and portable packages in both
+    32bit and 64bit variants
+  * building with both g++ and clang++
+  * building and running the unit tests
+  * building and running the test file test suite
+  * building with all optional features disabled
+
+# 5. Included libraries and their licenses
 
 MKVToolNix includes and uses the following libraries:
 
-## 4.1. avilib
+## 5.1. avilib
 
 Reading and writing avi files.
 
@@ -253,7 +287,7 @@ of the transcode package.
 License: GNU General Public License v2
 URL: http://www.transcoding.org/
 
-## 4.2. Boost's utf8_codecvt_facet
+## 5.2. Boost's utf8_codecvt_facet
 
 A class utf8_codecvt_facet, derived from std::codecvt<wchar_t, char>,
 which can be used to convert utf8 data in files into wchar_t strings
@@ -262,21 +296,21 @@ in the application.
 License: Boost Software License - Version 1.0
 URL: http://www.boost.org
 
-## 4.3. libEBML
+## 5.3. libEBML
 
 A C++ library to parse EBML files
 
 License: GNU Lesser General Public License v2.1
 URL: http://www.matroska.org/
 
-## 4.4. libMatroska
+## 5.4. libMatroska
 
 A C++ library to parse Matroska files
 
 License: GNU Lesser General Public License v2.1
 URL: http://www.matroska.org/
 
-## 4.5. librmff
+## 5.5. librmff
 
 librmff is short for 'RealMedia file format access library'. It aims
 at providing the programmer an easy way to read and write RealMedia
@@ -285,21 +319,21 @@ files.
 License: GNU Lesser General Public License v2.1
 URL: https://www.bunkus.org/videotools/librmff/index.html
 
-## 4.6. nlohmann's JSON
+## 5.6. nlohmann's JSON
 
 JSON for Modern C++
 
 License: MIT
 URL: https://github.com/nlohmann/json
 
-## 4.7. pugixml
+## 5.7. pugixml
 
 An XML processing library
 
 License: MIT
 URL: http://pugixml.org/
 
-## 4.8. utf8-cpp
+## 5.8. utf8-cpp
 
 UTF-8 with C++ in a Portable Way