ci: use local bin and native coverage merge in Makefile

- use binary coverage output for unit tests to enable
  native merge with integration coverage
- remove redundant test-coverage target declaration
- install test binary to project-local bin/ instead of using
  sudo to install to /usr/bin/
- replace external gocovmerge with native 'go tool covdata merge'

Signed-off-by: Klara Necasova <knecasov@redhat.com>

Author: knecasov

Makefile

@@ -43,21 +43,21 @@ test:
 
 .PHONY: test-coverage
 test-coverage: SHELL := /usr/bin/env bash
-test-coverage:
 	rm -rf "$(COVERDIR)"
-	mkdir -p "$(GOCOVERDIR)"
-	go test -coverpkg=./... -coverprofile="$(COVERDIR)/unit.out" -covermode=atomic ./...
+	mkdir -p "$(COVERDIR)/unit" "$(GOCOVERDIR)"
+	GOCOVERDIR="$(COVERDIR)/unit" go test -coverpkg=./... -covermode=atomic ./...
 	export GOCOVERDIR="$(GOCOVERDIR)"; \
 	set -e; \
-	$(MAKE) build GOFLAGS="-cover -covermode=atomic" && sudo install -D -m 755 $(PROJECT) /usr/bin/; \
+	$(MAKE) build GOFLAGS="-cover -covermode=atomic" && \
+	install -D -m 755 $(PROJECT) $(CURDIR)/bin/$(PROJECT); \
+	export PATH="$(CURDIR)/bin:$$PATH"; \
 	source .github/scripts/fdo-utils.sh; \
 	generate_certs; \
 	docker compose -f .github.qkg1.toppose/servers.yaml up -d --build; \
 	trap 'docker compose -f .github.qkg1.toppose/servers.yaml logs; docker compose -f .github.qkg1.toppose/servers.yaml down' EXIT; \
-	test_onboarding; \
-	go tool covdata textfmt -i="$(GOCOVERDIR)" -o="$(COVERDIR)/integration.out"
-	go install github.com/wadey/gocovmerge@latest
-	gocovmerge "$(COVERDIR)/unit.out" "$(COVERDIR)/integration.out" > "$(COVERDIR)/coverage.out"
+	test_onboarding
+	go tool covdata merge -i="$(COVERDIR)/unit,$(GOCOVERDIR)" -o="$(COVERDIR)/merged"
+	go tool covdata textfmt -i="$(COVERDIR)/merged" -o="$(COVERDIR)/coverage.out"
 	go tool cover -html="$(COVERDIR)/coverage.out" -o "$(COVERDIR)/coverage.html"
 
 .PHONY: vendor-tarball