Add testacc to Makefile

Makefile

@@ -10,10 +10,23 @@ bin:
 dev:
 	@TF_DEV=1 sh -c "$(CURDIR)/scripts/build.sh"
 
+# generate runs `go generate` to build the dynamically generated
+# source files.
+generate:
+	go generate ./...
+
 test:
 	go test $(TEST) $(TESTARGS) -timeout=10s
 	@$(MAKE) vet
 
+# testacc runs acceptance tests
+testacc: generate
+	@if [ "$(TEST)" = "./..." ]; then \
+		echo "ERROR: Set TEST to a specific package"; \
+		exit 1; \
+	fi
+	PACKER_ACC=1 go test $(TEST) -v $(TESTARGS) -timeout 45m
+
 testrace:
 	go test -race $(TEST) $(TESTARGS)
 
@@ -30,4 +43,4 @@ vet:
 		echo "and fix them if necessary before submitting the code for reviewal."; \
 	fi
 
-.PHONY: bin default test updatedeps vet
+.PHONY: bin default generate test testacc updatedeps vet