Better comments

packer/rpc/port_test.go

@@ -15,11 +15,12 @@ func addrPort(address net.Addr) string {
 func Test_netListenerInRange(t *testing.T) {
 	assert := asserts.NewTestingAsserts(t, true)
 
-	// Verify it selects an open port
+	// Open up port 10000 so that we take up a port
 	L1000, err := net.Listen("tcp", ":10000")
 	defer L1000.Close()
 	assert.Nil(err, "should be able to bind to port 10000")
 
+	// Verify it selects an open port
 	L := netListenerInRange(10000, 10005)
 	assert.NotNil(L, "should have a listener")
 	assert.Equal(addrPort(L.Addr()), "10001", "should bind to open port")