diff --git a/src/testdir/README.txt b/src/testdir/README.txt
index d3f11b23e..99c4f2313 100644
--- a/src/testdir/README.txt
+++ b/src/testdir/README.txt
@@ -58,3 +58,40 @@ feature.  These cannot use the "assert" functions, therefore they consist of a
 They modify the file and the result gets writtein in the test.out file.  This
 is then compared with the .ok file.  If they are equal the test passed.  If
 they differ the test failed.
+
+RUNNING THE TESTS:
+
+The below commands should be run from the src/testdir directory.
+
+To run a single test:
+
+    $ make test_<name>.res
+
+The file 'messages' contains the messages generated by the test script.  If a
+test fails, then the test.log file contains the error messages.  If all the
+tests are successful, then this file will be an empty file.
+
+To run a single test function from a test script:
+
+    $ ../vim -u NONE -S runtest.vim <test_file>.vim <function_name>
+
+To run all the tests:
+
+    $ make
+
+To run the test on MS-Windows using the MSVC nmake:
+
+    > nmake -f Make_dos.mak
+
+To run the tests with GUI Vim:
+
+    $ make GUI_FLAG=-g
+
+    or
+
+    $ make VIMPROG=../gvim
+
+To cleanup the temporary files after running the tests:
+
+    $ make clean
+