build: fix make test with distributed src

This patch addresses the functionality that is
missing for distributed make test source files.
In addition it extends the concept of colocating
test source code with functional source code
(eg. src/vcl/test). It also cleans up deficiencies
in the make test makefiles.

NOTE: Due to the way sphinx document tools work,
all test, all of the make test python code is
gathered using soft links into the directory:
.../build-root/build-test/src

Change summary:
- Remove 'make test' help details from
  main makefile help output to reduce clutter
  and redundant help output
- Move all generated build output to
  .../build-root/build-test
- Move test_vcl.py as first usecase for
  distributed core feature make test code
- Add test-wipe-all target and fix wipe targets
  to remove all generated files
- Fix 'make test-doc' to generate module
  documentation for all source files
- Remove unused targets in test/doc/Makefile
- Fix 'make test-shell'
- Fix test/ext Makefile to not generate
  bogus output

Type: fix
Fixes: a43c93f8554ad7418e31be3791b3fb71232f60ac

Change-Id: Icc2ddb81d474081c3ede4548ecd7a0624651f62d
Signed-off-by: Dave Wallace <dwallacelf@gmail.com>
diff --git a/test/Makefile b/test/Makefile
index 5a580b8..4dd77b9 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,15 +1,27 @@
 ASAN_OPTIONS?=verify_asan_link_order=0:detect_leaks=0:abort_on_error=1:unmap_shadow_on_exit=1:disable_coredump=0
 export ASAN_OPTIONS
 
-.PHONY: verify-test-dir
-
-FAILED_DIR=/tmp/vpp-failed-unittests/
-
-verify-test-dir:
+.PHONY: verify-env
+verify-env:
+ifndef WS_ROOT
+	$(error WS_ROOT is not set)
+endif
+ifndef BR
+	$(error BR is not set)
+endif
 ifndef TEST_DIR
 	$(error TEST_DIR is not set)
 endif
 
+export TEST_BR = $(BR)/build-test
+export TEST_DOC_BR = $(TEST_BR)/doc
+export BUILD_TEST_SRC = $(TEST_BR)/src
+FAILED_DIR=/tmp/vpp-failed-unittests/
+PLUGIN_TEST_DIRS=$(shell find $(PLUGIN_SRC_DIR) -type d -name test -exec echo -n " -d {}" \;)
+CORE_TEST_DIRS=$(shell find $(WS_ROOT)/src -not \( -path $(INTERN_PLUGIN_SRC_DIR) -prune \) -type d -name test -exec echo -n " -d {}" \;)
+VPP_TEST_DIRS=$(shell ls -d $(TEST_DIR)$(PLUGIN_TEST_DIRS)$(CORE_TEST_DIRS) $(EXTERN_TESTS))
+VPP_TEST_SRC=$(shell for dir in $(VPP_TEST_DIRS) ; do ls $$dir/*.py; done)
+
 .PHONY: verify-no-running-vpp
 
 ifdef VPP_ZOMBIE_NOCHECK
@@ -72,12 +84,12 @@
 UNITTEST_EXTRA_OPTS=$(UNITTEST_FAILFAST_OPTS) -d $(EXTERN_TESTS)
 endif
 
-VENV_PATH=$(TEST_DIR)/run/venv
+VENV_PATH=$(TEST_BR)/venv
 
 ifeq ($(TEST_DEBUG),1)
-TEST_RUN_DIR:=$(VENV_PATH)/run-debug
+VENV_RUN_DIR:=$(VENV_PATH)/run-debug
 else
-TEST_RUN_DIR:=$(VENV_PATH)/run
+VENV_RUN_DIR:=$(VENV_PATH)/run
 endif
 
 ifeq ($(PYTHON),)
@@ -91,18 +103,23 @@
 PIP_TOOLS_VERSION=3.8.0   # Keep in sync with requirements.txt
 PYTHON_DEPENDS=requirements-$(PYTHON_VERSION).txt
 SCAPY_SOURCE=$(shell find $(VENV_PATH)/lib/$(PYTHON_INTERP) -name site-packages)
-BUILD_COV_DIR=$(TEST_DIR)/coverage
+BUILD_COV_DIR=$(TEST_BR)/coverage
 
-PIP_TOOLS_INSTALL_DONE=$(TEST_RUN_DIR)/pip-tools-install-$(PYTHON_VERSION).done
-PIP_INSTALL_DONE=$(TEST_RUN_DIR)/pip-install-$(PYTHON_VERSION).done
-PIP_PATCH_DONE=$(TEST_RUN_DIR)/pip-patch-$(PYTHON_VERSION).done
-PAPI_INSTALL_DONE=$(TEST_RUN_DIR)/papi-install-$(PYTHON_VERSION).done
+PIP_TOOLS_INSTALL_DONE=$(VENV_RUN_DIR)/pip-tools-install-$(PYTHON_VERSION).done
+PIP_INSTALL_DONE=$(VENV_RUN_DIR)/pip-install-$(PYTHON_VERSION).done
+PIP_PATCH_DONE=$(VENV_RUN_DIR)/pip-patch-$(PYTHON_VERSION).done
+PAPI_INSTALL_DONE=$(VENV_RUN_DIR)/papi-install-$(PYTHON_VERSION).done
+PAPI_PYTHON_SRC_DIR=$(WS_ROOT)/src/vpp-api/python
+PAPI_WIPE_DIST=$(WS_ROOT)/src/vpp-api/vapi/__pycache__ \
+	$(PAPI_PYTHON_SRC_DIR)/build \
+	$(PAPI_PYTHON_SRC_DIR)/vpp_papi.egg-info \
+	$(PAPI_PYTHON_SRC_DIR)/vpp_papi/__pycache__
 
 PAPI_INSTALL_FLAGS=$(PIP_INSTALL_DONE) $(PIP_PATCH_DONE) $(PAPI_INSTALL_DONE)
 
 $(PIP_TOOLS_INSTALL_DONE):
 	@rm -rf $(VENV_PATH)
-	@mkdir -p $(TEST_RUN_DIR)
+	@mkdir -p $(VENV_RUN_DIR)
 	@virtualenv $(VENV_PATH) -p $(PYTHON_INTERP)
 	# pip version pinning
 	@bash -c "source $(VENV_PATH)/bin/activate && \
@@ -133,24 +150,25 @@
 	touch $@
 
 $(PAPI_INSTALL_DONE): $(PIP_PATCH_DONE)
-	@bash -c "source $(VENV_PATH)/bin/activate && $(PYTHON_INTERP) -m pip install -e $(WS_ROOT)/src/vpp-api/python"
+	@bash -c "source $(VENV_PATH)/bin/activate && $(PYTHON_INTERP) -m pip install -e $(PAPI_PYTHON_SRC_DIR)"
 	@touch $@
 
-.PHONY: update-deps clear-deps
+.PHONY: refresh-deps
 refresh-deps: clean-deps $(PYTHON_DEPENDS)
 
+.PHONY: clean-deps
 clean-deps:
 	@rm -f $(PYTHON_DEPENDS)
 
+INTERN_PLUGIN_SRC_DIR=$(WS_ROOT)/src/plugins
 ifneq ($(EXTERN_PLUGIN_SRC_DIR),)
 PLUGIN_SRC_DIR=$(EXTERN_PLUGIN_SRC_DIR)
 else
-PLUGIN_SRC_DIR=$(WS_ROOT)/src/plugins
+PLUGIN_SRC_DIR=$(INTERN_PLUGIN_SRC_DIR)
 endif
-PLUGIN_TEST_DIRS=$(shell find $(PLUGIN_SRC_DIR) -type d -name test -exec echo -n " -d {}" \;)
 
 define retest-func
-@env FORCE_FOREGROUND=$(FORCE_FOREGROUND) FAILED_DIR=$(FAILED_DIR) VENV_PATH=$(VENV_PATH) scripts/setsid_wrapper.sh $(FORCE_FOREGROUND) $(VENV_PATH)/bin/activate $(PYTHON_INTERP) $(PYTHON_PROFILE_OPTS) run_tests.py -d $(TEST_DIR)$(PLUGIN_TEST_DIRS) $(UNITTEST_EXTRA_OPTS) || env FAILED_DIR=$(FAILED_DIR) COMPRESS_FAILED_TEST_LOGS=$(COMPRESS_FAILED_TEST_LOGS) scripts/compress_failed.sh
+@env FORCE_FOREGROUND=$(FORCE_FOREGROUND) FAILED_DIR=$(FAILED_DIR) VENV_PATH=$(VENV_PATH) scripts/setsid_wrapper.sh $(FORCE_FOREGROUND) $(VENV_PATH)/bin/activate $(PYTHON_INTERP) $(PYTHON_PROFILE_OPTS) $(BUILD_TEST_SRC)/run_tests.py -d $(BUILD_TEST_SRC) $(UNITTEST_EXTRA_OPTS) || env FAILED_DIR=$(FAILED_DIR) COMPRESS_FAILED_TEST_LOGS=$(COMPRESS_FAILED_TEST_LOGS) scripts/compress_failed.sh
 endef
 
 .PHONY: sanity
@@ -159,8 +177,8 @@
 SANITY_IMPORT_VPP_PAPI_CMD=true
 SANITY_RUN_VPP_CMD=true
 else
-SANITY_IMPORT_VPP_PAPI_CMD=source $(VENV_PATH)/bin/activate && $(PYTHON_INTERP) sanity_import_vpp_papi.py
-SANITY_RUN_VPP_CMD=source $(VENV_PATH)/bin/activate && $(PYTHON_INTERP) sanity_run_vpp.py
+SANITY_IMPORT_VPP_PAPI_CMD=source $(VENV_PATH)/bin/activate && $(PYTHON_INTERP) $(BUILD_TEST_SRC)/sanity_import_vpp_papi.py
+SANITY_RUN_VPP_CMD=source $(VENV_PATH)/bin/activate && PYTHONPATH=$(BUILD_TEST_SRC) $(PYTHON_INTERP) $(BUILD_TEST_SRC)/sanity_run_vpp.py
 endif
 
 ifndef TEST_JOBS
@@ -175,7 +193,7 @@
 PARALLEL_ILLEGAL=1
 endif
 
-sanity: verify-no-running-vpp
+sanity: test-dep verify-no-running-vpp
 	@sys_req/dev_shm_size.sh
 	@bash -c "test $(PARALLEL_ILLEGAL) -eq 0 ||\
 	    (echo \"*******************************************************************\" &&\
@@ -196,21 +214,35 @@
 	         echo \"*******************************************************************\" &&\
 		 false)"
 
-.PHONY: ext
-ext:
-	make -C ext
+.PHONY: ext-test-apps
+ext-test-apps:
+	make -C ext test-apps
 
-test-dep: verify-test-dir $(PAPI_INSTALL_DONE)
+$(BUILD_TEST_SRC): verify-env
+	@mkdir -p $@
+	@for file in $(VPP_TEST_SRC); do if [ ! -e $(BUILD_TEST_SRC)/$$(basename $$file) ] ; then ln -s $$file $(BUILD_TEST_SRC) ; fi ; done
 
-test: verify-test-dir $(PAPI_INSTALL_DONE) ext sanity reset
+$(FAILED_DIR): reset
+	@mkdir -p $@
+
+.PHONY: test-dep
+test-dep: $(BUILD_TEST_SRC) $(PAPI_INSTALL_DONE) $(FAILED_DIR)
+
+.PHONY: test
+test: test-dep ext-test-apps sanity
 	$(call retest-func)
 
-retest: verify-test-dir sanity reset
+.PHONY: retest
+retest: verify-env sanity $(FAILED_DIR)
 	$(call retest-func)
 
-shell: verify-test-dir $(PAPI_INSTALL_DONE)
+.PHONY: shell
+shell: test-dep
 	@echo "source $(VENV_PATH)/bin/activate;\
+		cd $(BUILD_TEST_SRC);\
+		export PYTHONPATH=$(BUILD_TEST_SRC);\
 		echo '***';\
+		echo PYTHONPATH=$(BUILD_TEST_SRC);\
 		echo VPP_BUILD_DIR=$(VPP_BUILD_DIR);\
 		echo VPP_BIN=$(VPP_BIN);\
 		echo VPP_PLUGIN_PATH=$(VPP_PLUGIN_PATH);\
@@ -223,34 +255,44 @@
 		echo '***';\
 		exec </dev/tty" | bash -i
 
-.PHONY: wipe doc
-
+.PHONY: reset
 reset:
 	@rm -f /dev/shm/vpp-unittest-*
 	@rm -rf /tmp/vpp-unittest-*
+	@rm -f /tmp/api_post_mortem.*
 	@rm -rf $(FAILED_DIR)
-	@mkdir $(FAILED_DIR)
 
+.PHONY: wipe
 wipe: reset
 	@make -C ext clean
 	@rm -rf $(VENV_PATH)
-	@rm -f $(PAPI_INSTALL_FLAGS)
+	@rm -rf $(patsubst %,%/__pycache__, $(VPP_TEST_DIRS) $(BUILD_TEST_SRC))
 
-doc: verify-test-dir $(PIP_PATCH_DONE)
+$(TEST_DOC_BR):
+	@mkdir -p $@
 	@bash -c "source $(VENV_PATH)/bin/activate && \
 		  $(PYTHON_INTERP) -m pip install sphinx sphinx-rtd-theme"
-	@bash -c "source $(VENV_PATH)/bin/activate && make -C doc WS_ROOT=$(WS_ROOT) BR=$(BR) html"
+	@bash -c "source $(VENV_PATH)/bin/activate && make -C doc html"
+
+.PHONY: doc
+doc: $(BUILD_TEST_SRC) $(PIP_PATCH_DONE) $(TEST_DOC_BR)
+	@echo
+	@echo "Test Documentation URL: $(TEST_DOC_BR)/html/index.html"
+	@echo "Run 'make test-wipe-doc test-doc' to rebuild the test docs"
+	@echo
 
 .PHONY: wipe-doc
-
 wipe-doc:
-	@make -C doc wipe BR=$(BR)
+	@rm -rf $(TEST_DOC_BR)
 
-cov: wipe-cov reset ext verify-test-dir $(PAPI_INSTALL_DONE)
+$(BUILD_COV_DIR):
+	@mkdir -p $@
+
+.PHONY: cov
+cov: wipe-cov test-dep ext $(BUILD_COV_DIR)
 	@lcov --zerocounters --directory $(VPP_BUILD_DIR)
 	@test -z "$(EXTERN_COV_DIR)" || lcov --zerocounters --directory $(EXTERN_COV_DIR)
 	$(call retest-func)
-	@mkdir $(BUILD_COV_DIR)
 	@lcov --capture --directory $(VPP_BUILD_DIR) --output-file $(BUILD_COV_DIR)/coverage.info
 	@test -z "$(EXTERN_COV_DIR)" || lcov --capture --directory $(EXTERN_COV_DIR) --output-file $(BUILD_COV_DIR)/extern-coverage.info
 	@genhtml $(BUILD_COV_DIR)/coverage.info --output-directory $(BUILD_COV_DIR)/html
@@ -260,21 +302,23 @@
 	@test -z "$(EXTERN_COV_DIR)" || echo "Code coverage report for out-of-tree objects is in $(BUILD_COV_DIR)/extern-html/index.html"
 
 .PHONY: wipe-cov
-
 wipe-cov: wipe
 	@rm -rf $(BUILD_COV_DIR)
 
-.PHONY: papi-wipe
+.PHONY: wipe-papi
+wipe-papi:
+	@rm -rf $(PAPI_INSTALL_DONE) $(PAPI_WIPE_DIST)
 
-papi-wipe:
-	@rm -rf $(PAPI_INSTALL_DONE)
+.PHONY: wipe-all
+wipe-all: wipe wipe-papi wipe-doc wipe-cov
+	@rm -rf $(TEST_BR)
 
 .PHONY: checkstyle
-checkstyle: verify-test-dir $(PIP_INSTALL_DONE)
+checkstyle: $(BUILD_TEST_SRC) $(PIP_INSTALL_DONE)
 	@bash -c "source $(VENV_PATH)/bin/activate &&\
 		  $(PYTHON_INTERP) -m pip install pycodestyle"
 	@bash -c "source $(VENV_PATH)/bin/activate &&\
-		pycodestyle --show-source --ignore=W504,E126,E241,E226,E305,E704,E741,E722 --exclude=$(WS_ROOT)/test/_*.py -v $(WS_ROOT)/test/*.py $(PLUGIN_SRC_DIR)/*/test/*.py ||\
+		pycodestyle --show-source --ignore=W504,E126,E241,E226,E305,E704,E741,E722 -v $(BUILD_TEST_SRC)/*.py ||\
 		(echo \"*******************************************************************\" &&\
 		 echo \"* Test framework PEP8 compliance check FAILED \" &&\
 	         echo \"*******************************************************************\" &&\
@@ -283,77 +327,88 @@
 	@echo "* Test framework PEP8 compliance check passed"
 	@echo "*******************************************************************"
 
+.PHONY: help
 help:
 	@echo "Running tests:"
 	@echo ""
-	@echo " test                - build and run (basic) functional tests"
-	@echo " test-debug          - build and run (basic) functional tests (debug build)"
-	@echo " test-all            - build and run functional and extended tests"
-	@echo " test-all-debug      - build and run functional and extended tests (debug build)"
-	@echo " retest              - run functional tests"
-	@echo " retest-debug        - run functional tests (debug build)"
-	@echo " papi-wipe           - rebuild vpp_papi sources"
-	@echo " test-wipe           - wipe (temporary) files generated by unit tests"
-	@echo " test-shell          - enter shell with test environment"
-	@echo " test-shell-debug    - enter shell with test environment (debug build)"
+	@echo " test                   - build and run (basic) functional tests"
+	@echo " test-debug             - build and run (basic) functional tests (debug build)"
+	@echo " test-all               - build and run functional and extended tests"
+	@echo " test-all-debug         - build and run functional and extended tests (debug build)"
+	@echo " retest                 - run functional tests"
+	@echo " retest-debug           - run functional tests (debug build)"
+	@echo " retest-all             - run functional and extended tests"
+	@echo " retest-all-debug       - run functional and extended tests (debug build)"
+	@echo " test-cov               - generate code coverage report for test framework"
+	@echo " test-gcov                      - build and run functional tests (gcov build)"
+
+	@echo " test-wipe              - wipe (temporary) files generated by unit tests"
+	@echo " test-wipe-cov          - wipe code coverage report for test framework"
+	@echo " test-wipe-doc          - wipe documentation for test framework"
+	@echo " test-wipe-papi         - rebuild vpp_papi sources"
+	@echo " test-wipe-all          - wipe (temporary) files generated by unit tests, docs, and coverage"
+	@echo " test-shell             - enter shell with test environment"
+	@echo " test-shell-debug       - enter shell with test environment (debug build)"
+	@echo " test-checkstyle      - check PEP8 compliance for test framework"
+	@echo " test-refresh-deps    - refresh the Python dependencies for the tests"
 	@echo ""
 	@echo "Arguments controlling test runs:"
-	@echo " V=[0|1|2]            - set test verbosity level"
-	@echo "                        0=ERROR, 1=INFO, 2=DEBUG"
-	@echo " TEST_JOBS=[<n>|auto] - use <n> parallel processes for test execution or automatic discovery of maximum acceptable processes (default: 1)"
-	@echo " CACHE_OUTPUT=[0|1]   - cache VPP stdout/stderr and log as one block after test finishes (default: 1)"
-	@echo " FAILFAST=[0|1]       - fail fast if 1, complete all tests if 0"
-	@echo " TIMEOUT=<timeout>    - fail test suite if any single test takes longer than <timeout> (in seconds) to finish (default: 600)"
-	@echo " RETRIES=<n>          - retry failed tests <n> times"
-	@echo " DEBUG=<type>         - set VPP debugging kind"
-	@echo "    DEBUG=core        - detect coredump and load it in gdb on crash"
-	@echo "    DEBUG=gdb         - allow easy debugging by printing VPP PID"
-	@echo "                        and waiting for user input before running"
-	@echo "                        and tearing down a testcase"
-	@echo "    DEBUG=gdbserver   - run gdb inside a gdb server, otherwise"
-	@echo "                        same as above"
-	@echo " STEP=[yes|no]        - ease debugging by stepping through a testcase"
-	@echo " SANITY=[yes|no]      - perform sanity import of vpp-api/sanity vpp run before running tests (default: yes)"
-	@echo " EXTENDED_TESTS=[1|y] - used by 'test-all' & 'test-all-debug' to run extended tests"
-	@echo " TEST=<filter>        - filter the set of tests:"
-	@echo "    by file-name      - only run tests from specified file, e.g. TEST=test_bfd selects all tests from test_bfd.py"
-	@echo "    by file-suffix    - same as file-name, but 'test_' is omitted e.g. TEST=bfd selects all tests from test_bfd.py"
-	@echo "    by wildcard       - wildcard filter is <file>.<class>.<test function>, each can be replaced by '*'"
-	@echo "                        e.g. TEST='test_bfd.*.*' is equivalent to above example of filter by file-name"
-	@echo "                             TEST='bfd.*.*' is equivalent to above example of filter by file-suffix"
-	@echo "                             TEST='bfd.BFDAPITestCase.*' selects all tests from test_bfd.py which are part of BFDAPITestCase class"
-	@echo "                             TEST='bfd.BFDAPITestCase.test_add_bfd' selects a single test named test_add_bfd from test_bfd.py/BFDAPITestCase"
-	@echo "                             TEST='*.*.test_add_bfd' selects all test functions named test_add_bfd from all files/classes"
+	@echo " V=[0|1|2]              - set test verbosity level"
+	@echo "                          0=ERROR, 1=INFO, 2=DEBUG"
+	@echo " TEST_JOBS=[<n>|auto]   - use <n> parallel processes for test execution or automatic discovery of maximum acceptable processes (default: 1)"
+	@echo " CACHE_OUTPUT=[0|1]     - cache VPP stdout/stderr and log as one block after test finishes (default: 1)"
+	@echo " FAILFAST=[0|1]         - fail fast if 1, complete all tests if 0"
+	@echo " TIMEOUT=<timeout>      - fail test suite if any single test takes longer than <timeout> (in seconds) to finish (default: 600)"
+	@echo " RETRIES=<n>            - retry failed tests <n> times"
+	@echo " DEBUG=<type>           - set VPP debugging kind"
+	@echo "    DEBUG=core          - detect coredump and load it in gdb on crash"
+	@echo "    DEBUG=gdb           - allow easy debugging by printing VPP PID"
+	@echo "                          and waiting for user input before running"
+	@echo "                          and tearing down a testcase"
+	@echo "    DEBUG=gdbserver     - run gdb inside a gdb server, otherwise"
+	@echo "                          same as above"
+	@echo " STEP=[yes|no]          - ease debugging by stepping through a testcase"
+	@echo " SANITY=[yes|no]        - perform sanity import of vpp-api/sanity vpp run before running tests (default: yes)"
+	@echo " EXTENDED_TESTS=[1|y]   - used by '[re]test-all' & '[re]test-all-debug' to run extended tests"
+	@echo " TEST=<filter>          - filter the set of tests:"
+	@echo "    by file-name        - only run tests from specified file, e.g. TEST=test_bfd selects all tests from test_bfd.py"
+	@echo "    by file-suffix      - same as file-name, but 'test_' is omitted e.g. TEST=bfd selects all tests from test_bfd.py"
+	@echo "    by wildcard         - wildcard filter is <file>.<class>.<test function>, each can be replaced by '*'"
+	@echo "                          e.g. TEST='test_bfd.*.*' is equivalent to above example of filter by file-name"
+	@echo "                               TEST='bfd.*.*' is equivalent to above example of filter by file-suffix"
+	@echo "                               TEST='bfd.BFDAPITestCase.*' selects all tests from test_bfd.py which are part of BFDAPITestCase class"
+	@echo "                               TEST='bfd.BFDAPITestCase.test_add_bfd' selects a single test named test_add_bfd from test_bfd.py/BFDAPITestCase"
+	@echo "                               TEST='*.*.test_add_bfd' selects all test functions named test_add_bfd from all files/classes"
 	@echo ""
-	@echo " VPP_ZOMBIE_NOCHECK=1 - skip checking for vpp (zombie) processes (CAUTION)"
-	@echo " COREDUMP_SIZE=<size> - pass <size> as unix { coredump-size <size> } argument to vpp"
-	@echo "                        e.g. COREDUMP_SIZE=4g"
-	@echo "                             COREDUMP_SIZE=unlimited"
-	@echo " COREDUMP_COMPRESS=1  - compress core files if not debugging them"
-	@echo " EXTERN_TESTS=<path>  - path to out-of-tree test_<name>.py files containing test cases"
-	@echo " EXTERN_PLUGINS=<path>- path to out-of-tree plugins to be loaded by vpp under test"
-	@echo " EXTERN_COV_DIR=<path>- path to out-of-tree prefix, where source, object and .gcda files can be found for coverage report"
+	@echo " VPP_ZOMBIE_NOCHECK=1   - skip checking for vpp (zombie) processes (CAUTION)"
+	@echo " COREDUMP_SIZE=<size>   - pass <size> as unix { coredump-size <size> } argument to vpp"
+	@echo "                          e.g. COREDUMP_SIZE=4g"
+	@echo "                               COREDUMP_SIZE=unlimited"
+	@echo " COREDUMP_COMPRESS=1    - compress core files if not debugging them"
+	@echo " EXTERN_TESTS=<path>    - path to out-of-tree test_<name>.py files containing test cases"
+	@echo " EXTERN_PLUGINS=<path>  - path to out-of-tree plugins to be loaded by vpp under test"
+	@echo " EXTERN_COV_DIR=<path>  - path to out-of-tree prefix, where source, object and .gcda files can be found for coverage report"
 	@echo ""
-	@echo " PROFILE=1            - enable profiling of test framework via cProfile module"
-	@echo " PROFILE_SORT_BY=opt  - sort profiling report by opt - consult cProfile documentation for possible values (default: cumtime)"
-	@echo " PROFILE_OUTPUT=file  - output profiling info to file - use absolute path (default: stdout)"
+	@echo " PROFILE=1              - enable profiling of test framework via cProfile module"
+	@echo " PROFILE_SORT_BY=opt    - sort profiling report by opt - consult cProfile documentation for possible values (default: cumtime)"
+	@echo " PROFILE_OUTPUT=file    - output profiling info to file - use absolute path (default: stdout)"
 	@echo ""
-	@echo " TEST_DEBUG=1         - turn on debugging of the test framework itself (expert)"
+	@echo " TEST_DEBUG=1           - turn on debugging of the test framework itself (expert)"
 	@echo ""
-	@echo " SKIP_AARCH64=1       - skip tests that are failing on the ARM platorm in FD.io CI"
+	@echo " SKIP_AARCH64=1         - skip tests that are failing on the ARM platorm in FD.io CI"
 	@echo ""
-	@echo " SOCKET=1             - Communicate with VPP over Unix domain socket instead of SHM"
+	@echo " SOCKET=1               - Communicate with VPP over Unix domain socket instead of SHM"
 	@echo ""
-	@echo " RND_SEED=seed        - Seed RND with given seed"
+	@echo " RND_SEED=seed          - Seed RND with given seed"
 	@echo ""
 	@echo "Creating test documentation"
-	@echo " test-doc            - generate documentation for test framework"
-	@echo " test-wipe-doc       - wipe documentation for test framework"
+	@echo " test-doc               - generate documentation for test framework"
+	@echo " test-wipe-doc          - wipe documentation for test framework"
 	@echo ""
 	@echo "Creating test code coverage report"
-	@echo " test-cov            - generate code coverage report for test framework"
-	@echo " test-wipe-cov       - wipe code coverage report for test framework"
+	@echo " test-cov               - generate code coverage report for test framework"
+	@echo " test-wipe-cov          - wipe code coverage report for test framework"
 	@echo ""
 	@echo "Verifying code-style"
-	@echo " test-checkstyle     - check PEP8 compliance"
+	@echo " test-checkstyle        - check PEP8 compliance"
 	@echo ""