First basic version that works

4 files changed, 124 insertions, 0 deletions

diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..e6f2ddd
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module go.awhk.org/pipeln
+
+go 1.15
+
+require github.com/stretchr/testify v1.7.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..acb88a4
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,11 @@
+github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
diff --git a/pipeln.go b/pipeln.go
new file mode 100644
index 0000000..8ff6a62
--- /dev/null
+++ b/pipeln.go
@@ -0,0 +1,78 @@
+// SPDX-License-Identifier: CC0-1.0
+
+package pipeln
+
+import (
+	"context"
+	"errors"
+	"net"
+)
+
+var (
+	ErrBadAddress = errors.New("bad address")
+	ErrClosed     = errors.New("closed listener")
+)
+
+type addr struct {
+	ln *PipeListenerDialer
+}
+
+var _ net.Addr = addr{}
+
+func (addr) Network() string {
+	return "pipe"
+}
+
+func (a addr) String() string {
+	return "pipe:" + a.ln.addr
+}
+
+// PipeListener can be used to simulate client-server interaction within
+// the same process. Useful for testing. Somehow the Go standard library
+// provides net.Pipe but no net.PipeListener.
+type PipeListenerDialer struct {
+	addr  string
+	conns chan net.Conn
+	done  chan struct{}
+}
+
+var _ net.Listener = &PipeListenerDialer{}
+
+func (ln *PipeListenerDialer) Accept() (net.Conn, error) {
+	select {
+	case conn := <-ln.conns:
+		return conn, nil
+	case <-ln.done:
+		return nil, ErrClosed
+	}
+}
+
+func (ln *PipeListenerDialer) Addr() net.Addr {
+	return addr{ln}
+}
+
+func (ln *PipeListenerDialer) Close() error {
+	close(ln.done)
+	return nil
+}
+
+func (ln *PipeListenerDialer) Dial(_, addr string) (net.Conn, error) {
+	if addr != ln.addr {
+		return nil, ErrBadAddress
+	}
+	s, c := net.Pipe()
+	select {
+	case <-ln.done:
+		return nil, ErrClosed
+	case ln.conns <- s:
+		return c, nil
+	}
+}
+
+func (ln *PipeListenerDialer) DialContext(_ context.Context, network, addr string) (net.Conn, error) {
+	return ln.Dial(network, addr)
+}
+
+func New(addr string) *PipeListenerDialer {
+	return &PipeListenerDialer{addr, make(chan net.Conn), make(chan struct{})}
+}
diff --git a/pipeln_test.go b/pipeln_test.go
new file mode 100644
index 0000000..e5de8d0
--- /dev/null
+++ b/pipeln_test.go
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: CC0-1.0
+
+package pipeln
+
+import (
+	"context"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func Test(t *testing.T) {
+	ln := New("test:80")
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/endpoint", func(w http.ResponseWriter, _ *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	})
+	srv := http.Server{Handler: mux}
+	go srv.Serve(ln)
+
+	client := http.Client{Transport: &http.Transport{Dial: ln.Dial}}
+	resp, err := client.Get("http://test/endpoint")
+	require.NoError(t, err)
+	assert.Equal(t, http.StatusOK, resp.StatusCode)
+
+	srv.Shutdown(context.Background())
+}