ktest: Add POST/PRE_BUILD options

There are some cases that a patch may be needed to apply to the kernel
in patchcheck or bisect tests. Adding a PRE_BUILD option to apply the
patch and POST_BUILD to remove it, allows for this to be done easily.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/tools/testing/ktest/sample.conf b/tools/testing/ktest/sample.conf
index 0e5f764..1092e47 100644
--- a/tools/testing/ktest/sample.conf
+++ b/tools/testing/ktest/sample.conf
@@ -293,6 +293,38 @@
 # or on some systems:
 #POST_INSTALL = ssh user@target /sbin/dracut -f /boot/initramfs-test.img $KERNEL_VERSION
 
+# If there is a script that you require to run before the build is done
+# you can specify it with PRE_BUILD.
+#
+# One example may be if you must add a temporary patch to the build to
+# fix a unrelated bug to perform a patchcheck test. This will apply the
+# patch before each build that is made. Use the POST_BUILD to do a git reset --hard
+# to remove the patch.
+#
+# (default undef)
+#PRE_BUILD = cd ${BUILD_DIR} && patch -p1 < /tmp/temp.patch
+
+# To specify if the test should fail if the PRE_BUILD fails,
+# PRE_BUILD_DIE needs to be set to 1. Otherwise the PRE_BUILD
+# result is ignored.
+# (default 0)
+# PRE_BUILD_DIE = 1
+
+# If there is a script that should run after the build is done
+# you can specify it with POST_BUILD.
+#
+# As the example in PRE_BUILD, POST_BUILD can be used to reset modifications
+# made by the PRE_BUILD.
+#
+# (default undef)
+#POST_BUILD = cd ${BUILD_DIR} && git reset --hard
+
+# To specify if the test should fail if the POST_BUILD fails,
+# POST_BUILD_DIE needs to be set to 1. Otherwise the POST_BUILD
+# result is ignored.
+# (default 0)
+#POST_BUILD_DIE = 1
+
 # Way to reboot the box to the test kernel.
 # Only valid options so far are "grub" and "script"
 # (default grub)