type testConn struct {
	readMu   sync.Mutex // for TestHandlerBodyClose
	readBuf  bytes.Buffer
	writeBuf bytes.Buffer
	closec   chan bool // 1-buffered; receives true when Close is called
	noopConn
}

func newTestConn() *testConn {
	return &testConn{closec: make(chan bool, 1)}
}

func (c *testConn) Read(b []byte) (int, error) {
	c.readMu.Lock()
	defer c.readMu.Unlock()
	return c.readBuf.Read(b)
}