test: use -json to prevent output buffering

When testing multiple packages, "go test" buffers all the output until the tests finish, even with verbose (-v) mode. This is because parallel tests could otherwise interleave their output and be difficult to read. Across packages, tests could have the same name.

In JSON mode (-json), there's an explicit "Package" field in the output, so "go test" can safely print output as it comes in.

This ensures that if the tests are running for a long time due to server errors, the user can see the output as it comes in. Otherwise, Jenkins may terminate the job at the configured 40m deadline, before any meaningful output is printed.

golang/go#46959

Change-Id: Ia6e0bf92e927b14f56e601839b27141bb6dd1298

GNUmakefile

@@ -72,7 +72,7 @@ test: fmtcheck
 		xargs -t -n4 go test $(TESTARGS) -timeout=30s -parallel=4
 
 testacc: fmtcheck
-	TF_ACC_TERRAFORM_CACHE_DIR=/tmp TF_ACC_TERRAFORM_VERSION=1.1.7 TF_LOG=DEBUG TF_ACC=1 go test $(TEST) -v $(TESTARGS) -timeout 120m
+	TF_ACC_TERRAFORM_CACHE_DIR=/tmp TF_ACC_TERRAFORM_VERSION=1.1.7 TF_LOG=DEBUG TF_ACC=1 go test $(TEST) -v -json $(TESTARGS) -timeout 120m
 
 vet:
 	@echo "go vet ."