create e2e test for auth buttons (#1907)

This PR adds a few helpful additions regarding authentication.

Changes:
* e2e tests are now run on test_oauth via a passed config.yaml 
* node dev server correctly handles `/login` and `/logout` endpoints to make developing for auth easier
* Introduced auth e2e tests to check that buttons display and work

client/Makefile

@@ -3,6 +3,8 @@ include ../common.mk
 ANNOTATIONS := $(if $(ANNOTATIONS),$(ANNOTATIONS),../server/test/fixtures/pbmc3k-annotations.csv)
 ANNOTATIONS_FILENAME := $(shell basename $(ANNOTATIONS))
 
+CXG_CONFIG := $(if $(CXG_CONFIG), $(CXG_CONFIG), ./__tests__/e2e/test_config.yaml)
+
 # Packaging
 .PHONY: clean
 clean:
@@ -31,7 +33,7 @@ start-frontend:
 .PHONY: smoke-test
 smoke-test:
 	start_server_and_test \
-		'CXG_OPTIONS="--disable-annotations" $(MAKE) start-server' \
+		'CXG_OPTIONS="--config-file $(CXG_CONFIG)" $(MAKE) start-server' \
 		$(CXG_SERVER_PORT) \
 		'CXG_URL_BASE="http://localhost:$(CXG_SERVER_PORT)" npm run e2e -- --verbose false'