ci: run doctests on kernel crate

Author: ppannuto

Makefile

@@ -46,12 +46,16 @@ ci-travis:
 	@printf "$$(tput bold)*****************$$(tput sgr0)\n"
 	@printf "$$(tput bold)* CI: Libraries *$$(tput sgr0)\n"
 	@printf "$$(tput bold)*****************$$(tput sgr0)\n"
-	@CI=true cd libraries/tock-cells && cargo test
-	@CI=true cd libraries/tock-register-interface && cargo test
+	@cd libraries/tock-cells && CI=true cargo test
+	@cd libraries/tock-register-interface && CI=true cargo test
 	@printf "$$(tput bold)**************$$(tput sgr0)\n"
 	@printf "$$(tput bold)* CI: Syntax *$$(tput sgr0)\n"
 	@printf "$$(tput bold)**************$$(tput sgr0)\n"
 	@CI=true $(MAKE) allcheck
+	@printf "$$(tput bold)****************$$(tput sgr0)\n"
+	@printf "$$(tput bold)* CI: DocTests *$$(tput sgr0)\n"
+	@printf "$$(tput bold)****************$$(tput sgr0)\n"
+	@cd kernel && CI=true TOCK_KERNEL_VERSION=ci_test cargo test
 	@printf "$$(tput bold)*******************$$(tput sgr0)\n"
 	@printf "$$(tput bold)* CI: Compilation *$$(tput sgr0)\n"
 	@printf "$$(tput bold)*******************$$(tput sgr0)\n"