reproducible-builds.rst: show how to build a single package

Add a bit to the "Can we prove the project is reproducible?" section to
show how OEQA_REPRODUCIBLE_TEST_TARGET can be used to test a single
package (rather than the world build), as this may be useful for
maintainers.

[YOCTO #15619]

(From yocto-docs rev: 6fda76e3a879e72979b3678ce583604783f178bb)

Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
(cherry picked from commit c4bc09f61621938086be377653121d6b4e62b570)
Signed-off-by: Antonin Godard <antonin.godard@bootlin.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 15 insertions, 7 deletions

diff --git a/documentation/test-manual/reproducible-builds.rst b/documentation/test-manual/reproducible-builds.rst
index a51cc15a19..d383a3ebc4 100644
--- a/documentation/test-manual/reproducible-builds.rst
+++ b/documentation/test-manual/reproducible-builds.rst
@@ -91,13 +91,21 @@ run::
 
    oe-selftest -r reproducible.ReproducibleTests.test_reproducible_builds
 
-This defaults to including a ``world`` build so, if other layers are added, it would
-also run the tests for recipes in the additional layers. Different build targets
-can be defined using the :term:`OEQA_REPRODUCIBLE_TEST_TARGET` variable in ``local.conf``.
-The first build will be run using :ref:`Shared State <overview-manual/concepts:Shared State>` if
-available, the second build explicitly disables
-:ref:`Shared State <overview-manual/concepts:Shared State>` except for recipes defined in
-the :term:`OEQA_REPRODUCIBLE_TEST_SSTATE_TARGETS` variable, and builds on the
+This defaults to including a ``world`` build so, if other layers are added, it
+would also run the tests for recipes in the additional layers. Different build
+targets can be defined using the :term:`OEQA_REPRODUCIBLE_TEST_TARGET` variable
+in ``local.conf``. For example, running reproducibility tests for only the
+``python3-numpy`` recipe can be done by setting::
+
+   OEQA_REPRODUCIBLE_TEST_TARGET = "python3-numpy"
+
+in local.conf before running the ``oe-selftest`` command shown above.
+
+Reproducibility builds the target list twice. The first build will be run using
+:ref:`Shared State <overview-manual/concepts:Shared State>` if available, the
+second build explicitly disables :ref:`Shared State
+<overview-manual/concepts:Shared State>` except for recipes defined in the
+:term:`OEQA_REPRODUCIBLE_TEST_SSTATE_TARGETS` variable, and builds on the
 specific host the build is running on. This means we can test reproducibility
 builds between different host distributions over time on the Autobuilder.