ci: use gotestsum for running tests

`gotestsum` has user friendlier output that emits final summary, also it can emit junit xml file for
automated analysis instead of current format that should significantly
ease automated analysis of CI.

.travis.yml

@@ -58,4 +58,7 @@ install:
   - if [[ "$RUN_UI_TESTS" ]]; then . $HOME/.nvm/nvm.sh && cd ui && nvm use && cd .. ; fi
 
 script:
-  - sudo -E "PATH=$PATH" make travis
+  - sudo -E "PATH=$PATH" GOTESTSUM_JUNITFILE=/tmp/results.xml make travis
+
+after_script:
+  - cat /tmp/results.xml

GNUmakefile

@@ -8,6 +8,8 @@ GIT_DIRTY := $(if $(shell git status --porcelain),+CHANGES)
 GO_LDFLAGS := "-X github.com/hashicorp/nomad/version.GitCommit=$(GIT_COMMIT)$(GIT_DIRTY)"
 GO_TAGS =
 
+GO_TEST_CMD = $(if $(shell which gotestsum),gotestsum --,go test)
+
 default: help
 
 ifeq (,$(findstring $(THIS_OS),Darwin Linux FreeBSD))
@@ -153,6 +155,7 @@ deps:  ## Install build and development dependencies
 	go get -u github.com/a8m/tree/cmd/tree
 	go get -u github.com/magiconair/vendorfmt/cmd/vendorfmt
 	go get -u github.com/golang/protobuf/protoc-gen-go
+	go get -u gotest.tools/gotestsum
 
 .PHONY: lint-deps
 lint-deps: ## Install linter dependencies
@@ -261,7 +264,7 @@ test: ## Run the Nomad test suite and/or the Nomad UI test suite
 .PHONY: test-nomad
 test-nomad: dev ## Run Nomad test suites
 	@echo "==> Running Nomad test suites:"
-	$(if $(ENABLE_RACE),GORACE="strip_path_prefix=$(GOPATH)/src") go test \
+	$(if $(ENABLE_RACE),GORACE="strip_path_prefix=$(GOPATH)/src") $(GO_TEST_CMD) \
 		$(if $(ENABLE_RACE),-race) $(if $(VERBOSE),-v) \
 		-cover \
 		-timeout=15m \