Add test coverage to the makefile

Makefile

@@ -10,6 +10,7 @@ COMMIT_DATETIME := $(shell git log -1 --format=%cd --date=iso8601)
 LDFLAGS := -X git.omicron.one/omicron/linkshare/internal/version.Version=$(VERSION) \
            -X git.omicron.one/omicron/linkshare/internal/version.GitCommit=$(COMMIT) \
            -X "git.omicron.one/omicron/linkshare/internal/version.CommitDateTime=$(COMMIT_DATETIME)"
+OPEN = xdg-open
 
 
 all: build
@@ -25,7 +26,10 @@ $(BINARIES): %: $(BINARY_DIR)
 	go build -ldflags '$(LDFLAGS)' -o $(BINARY_DIR)/$@ ./cmd/$@/
 
 test:
-	go test ./...
+	mkdir -p reports/coverage/
+	go test ./... -coverprofile=reports/coverage/coverage.out
+	go tool cover -html=reports/coverage/coverage.out -o reports/coverage/coverage.html && $(OPEN) reports/coverage/coverage.html
+
 
 validate:
 	@test -z "$(shell gofumpt -l .)" && echo "No files need formatting" || (echo "Incorrect formatting in:"; gofumpt  -l .; exit 1)
@@ -33,6 +37,7 @@ validate:
 
 clean:
 	rm -rf $(BINARY_DIR)
+	rm -rf reports
 	go clean
 
 run: $(LINKSERV)