feat(test): check format conditions in test

And add option '--fmt' in build script to gofmt files automatically.

build

@@ -7,6 +7,12 @@ fi
 
 export GOBIN=${PWD}/bin
 export GOPATH=${PWD}
+export GOFMTPATH="./bench ./config ./discovery ./error etcd.go ./http ./log ./machines ./metrics ./mod profile.go ./server ./store ./tests"
+
+# Don't surprise user by formatting their codes by stealth
+if [ "$1" == "--fmt" ]; then
+	gofmt -s -w -l $GOFMTPATH
+fi
 
 go install github.com/coreos/etcd
 go install github.com/coreos/etcd/bench

test.sh

@@ -2,6 +2,13 @@
 
 . ./build
 
+fmtRes=`gofmt -l $GOFMTPATH`
+if [ "$fmtRes" != "" ]; then
+	echo "Failed to pass golang format checking."
+	echo "Please gofmt modified go files, or run './build --fmt'."
+	exit 1
+fi
+
 go test -i ./http
 go test -v ./http