selftest: Introduce scenario_test

This covers some unit tests for scenario module (Scenario class).

Change-Id: I4c80047bb03ae8254c192057007fa7df84478605
diff --git a/selftest/scenario_test/scenario_test.ok.ign b/selftest/scenario_test/scenario_test.ok.ign
new file mode 100644
index 0000000..a19fb8b
--- /dev/null
+++ b/selftest/scenario_test/scenario_test.ok.ign
@@ -0,0 +1,2 @@
+/[^ ]*/selftest/	[PATH]/selftest/
+\.py:[0-9]*	.py:[LINENR]