Makefile dynamic install of go-related tooling is not working right

GO_JUNIT_REPORT:=$(shell which go-junit-report)
GOCOVER_COBERTURA:=$(shell which gocover-cobertura)
test:
ifeq (,$(GO_JUNIT_REPORT))
        go get -u github.com/jstemmer/go-junit-report
        @GO_JUNIT_REPORT=$(GOPATH)/bin/go-junit-report
endif
ifeq (,$(GOCOVER_COBERTURA))
        go get -u github.com/t-yuki/gocover-cobertura
        @GOCOVER_COBERTURA=$(GOPATH)/bin/gocover-cobertura
endif
        @mkdir -p ./tests/results
        @go test -mod=vendor -v -coverprofile ./tests/results/go-test-coverage.out -covermode count ./... 2>&1 | tee ./tests/results/go-test-results.out ;\
        RETURN=$$? ;\
        $(GO_JUNIT_REPORT) < ./tests/results/go-test-results.out > ./tests/results/go-test-results.xml ;\
        $(GOCOVER_COBERTURA) < ./tests/results/go-test-coverage.out > ./tests/results/go-test-coverage.xml ;\
        exit $$RETURN