Merge pull request #920 from Blizzard/selftest-fix

small fix in self-test module.

modules/self-test/test_runner.lua

@@ -59,6 +59,7 @@
 		local passed = 0
 		local failed = 0
 
+		if test.suite ~= nil then
 			for testName, testFunction in pairs(test.suite) do
 				test.testName = testName
 				test.testFunction = testFunction
@@ -69,6 +70,7 @@
 					failed = failed + nf
 				end
 			end
+		end
 
 		return passed, failed
 	end