feat: comprehensive test suite (Phase 4.2) (#12)

Makefile

@@ -3,7 +3,7 @@ BUILD_DIR=bin
 GO=go
 GOFLAGS=-v
 
-.PHONY: build test lint clean
+.PHONY: build test lint clean cover
 
 build:
 	$(GO) build $(GOFLAGS) -o $(BUILD_DIR)/$(BINARY_NAME) ./cmd/exploredns
@@ -11,9 +11,13 @@ build:
 test:
 	$(GO) test -v -race -coverprofile=coverage.out ./...
 
+cover: test
+	$(GO) tool cover -func=coverage.out
+	$(GO) tool cover -html=coverage.out -o coverage.html
+
 lint:
 	$(GO) vet ./...
 
 clean:
 	rm -rf $(BUILD_DIR)
-	rm -f coverage.out
+	rm -f coverage.out coverage.html