Add tests and run info to README.md and Makefile.

Makefile

@@ -61,7 +61,10 @@ release: REMOTE_DIR ?= $(error "can't release, REMOTE_DIR not set")
 release: $(ARCHIVE)
 	scp $< $(REMOTE):$(REMOTE_DIR)/$(ARCHIVE)
 
+test: $(GOCC) dependencies
+	$(GO) test ./...
+
 clean:
 	rm -rf node_exporter .deps
 
-.PHONY: dependencies clean release
+.PHONY: clean default dependencies release test

README.md

@@ -3,6 +3,15 @@
 Prometheus exporter for machine metrics, written in Go with pluggable metric
 collectors.
 
+## Building and running
+
+    make
+    ./node_exporter <flags>
+
+## Running tests
+
+    make test
+
 ## Available collectors
 
 By default the build will include the native collectors that expose information