Add README.md

2 files changed, 36 insertions, 2 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..bb07501
--- /dev/null
+++ b/README.md
@@ -0,0 +1,34 @@
+`pipeln` implements a trivial type, `PipeListenerDialer`, that can be
+used both as a `net.Listener` and as a dialer. It uses `net.Pipe` to
+connect server and clients so that testing client-server communication
+becomes easier.
+
+Several dialer methods are available, and happen (as there is no
+`net.Dialer` interface) to be compatible with both `net.Transport` and
+`grpc.WithContextDialer`.
+
+For instance:
+
+```go
+func TestHTTP(t *testing.T) {
+	ln := pipeln.New("test:80")
+
+	srv := http.Server{}
+	go srv.Serve(ln)
+
+	client := http.Client{Transport: &http.Transport{Dial: ln.Dial}}
+
+	// ...
+}
+
+func TestGRPC(t *testing.T) {
+	ln := pipeln.New("test")
+
+	srv := grpc.NewServer()
+	go srv.Serve(ln)
+
+	client, _ := grpc.Dial("test", grpc.WithContextDialer(ln.DialContextAddr), grpc.WithInsecure())
+
+	// ...
+}
+```
diff --git a/pipeln.go b/pipeln.go
index 507ab33..c836f28 100644
--- a/pipeln.go
+++ b/pipeln.go
@@ -62,10 +62,10 @@ func (ln *PipeListenerDialer) Dial(_, addr string) (net.Conn, error) {
 	}
 	s, c := net.Pipe()
 	select {
-	case <-ln.done:
-		return nil, ErrClosed
 	case ln.conns <- s:
 		return c, nil
+	case <-ln.done:
+		return nil, ErrClosed
 	}
 }