ref-manual/variables.rst: document TESTSDK_SUITES

The TESTSDK_SUITES variable can be used to control the list of test
modules run with the testsdk class.

(From yocto-docs rev: fbc6db0ab525c7e46774c01fc595f30d6d0fe3c1)

Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/classes.rst

@@ -3069,6 +3069,9 @@ using the following::
 
    $ bitbake -c testsdk image
 
+The list of test modules that are run can be controlled with the
+:term:`TESTSDK_SUITES` variable.
+
 .. note::
 
    Best practices include using :term:`IMAGE_CLASSES` rather than

documentation/ref-manual/variables.rst

@@ -10165,6 +10165,12 @@ system and gives an overview of their function and contents.
       :term:`TESTIMAGE_FAILED_QA_ARTIFACTS`  lists space-separated paths on the
       target to retrieve onto the host.
 
+   :term:`TESTSDK_SUITES`
+      When using the :ref:`ref-classes-testsdk` class, the
+      :term:`TESTSDK_SUITES` variable can be used to control the list of test
+      modules to run. The default value for this variable is an empty string
+      and all test modules that can be found are run.
+
    :term:`THISDIR`
       The directory in which the file BitBake is currently parsing is
       located. Do not manually set this variable.