ktest: Add IF and ELSE to config sections

Add IF keyword to sections within the config. Also added an ELSE
keyword that allows different config options to be set for a given
section.

For example:

TYPE := 1
STATUS := 0

DEFAULTS IF ${TYPE}
[...]
ELSE IF ${STATUS}
[...]
ELSE
[...]

The above will process the first section as $TYPE is true. If it
was false, it would process the last section as $STATUS is false.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/tools/testing/ktest/sample.conf b/tools/testing/ktest/sample.conf
index 67bc4e0..6a0a0ba 100644
--- a/tools/testing/ktest/sample.conf
+++ b/tools/testing/ktest/sample.conf
@@ -72,6 +72,44 @@
 # the same option name under the same test or as default
 # ktest will fail to execute, and no tests will run.
 #
+# Both TEST_START and DEFAULTS sections can also have the IF keyword
+# The value after the IF must evaluate into a 0 or non 0 positive
+# integer, and can use the config variables (explained below).
+#
+# DEFAULTS IF ${IS_X86_32}
+#
+# The above will process the DEFAULTS section if the config
+# variable IS_X86_32 evaluates to a non zero positive integer
+# otherwise if it evaluates to zero, it will act the same
+# as if the SKIP keyword was used.
+#
+# The ELSE keyword can be used directly after a section with
+# a IF statement.
+#
+# TEST_START IF ${RUN_NET_TESTS}
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-network
+#
+# ELSE
+#
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-normal
+#
+#
+# The ELSE keyword can also contain an IF statement to allow multiple
+# if then else sections. But all the sections must be either
+# DEFAULT or TEST_START, they can not be a mixture.
+#
+# TEST_START IF ${RUN_NET_TESTS}
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-network
+#
+# ELSE IF ${RUN_DISK_TESTS}
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-tests
+#
+# ELSE IF ${RUN_CPU_TESTS}
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-cpu
+#
+# ELSE
+# BUILD_TYPE = useconfig:${CONFIG_DIR}/config-network
+#
 
 #### Config variables ####
 #