make test: add make test-shell[-debug] targets

This starts a bash with the same environment as the test framework
uses, allowing easy debugging.

Change-Id: I956deda913b73dae5b1e1976417834ae4731f88a
Signed-off-by: Klement Sekera <ksekera@cisco.com>
diff --git a/Makefile b/Makefile
index 7faba3b..f0173cc 100644
--- a/Makefile
+++ b/Makefile
@@ -86,6 +86,8 @@
 	@echo " test-debug          - build and run (basic) functional tests (debug build)"
 	@echo " test-all            - build and run (all) functional tests"
 	@echo " test-all-debug      - build and run (all) functional tests (debug build)"
+	@echo " test-shell          - enter shell with test environment"
+	@echo " test-shell-debug    - enter shell with test environment (debug build)"
 	@echo " test-wipe           - wipe files generated by unit tests"
 	@echo " retest              - run functional tests"
 	@echo " retest-debug        - run functional tests (debug build)"
@@ -247,6 +249,12 @@
 test-wipe:
 	@make -C test wipe
 
+test-shell: bootstrap
+	$(call test,vpp_lite,vpp_lite,shell)
+
+test-shell-debug: bootstrap
+	$(call test,vpp_lite,vpp_lite_debug,shell)
+
 test-doc:
 	@make -C test doc