Add ndt7test package for creating an ndt7 server for unit tests (#319)

* Add ndt7/ndt7test
* Verify that TCPInfo is non-nil
* Add unit test for ndt7test logic

ndt7/handler/handler.go

@@ -188,7 +188,8 @@ func getData(conn *websocket.Conn) (*model.ArchivalData, error) {
 
 func upRate(m []model.Measurement) float64 {
 	var mbps float64
-	if len(m) > 0 {
+	// NOTE: on non-Linux platforms, TCPInfo will be nil.
+	if len(m) > 0 && m[len(m)-1].TCPInfo != nil {
 		// Convert to Mbps.
 		mbps = 8 * float64(m[len(m)-1].TCPInfo.BytesReceived) / float64(m[len(m)-1].TCPInfo.ElapsedTime)
 	}
@@ -197,7 +198,8 @@ func upRate(m []model.Measurement) float64 {
 
 func downRate(m []model.Measurement) float64 {
 	var mbps float64
-	if len(m) > 0 {
+	// NOTE: on non-Linux platforms, TCPInfo will be nil.
+	if len(m) > 0 && m[len(m)-1].TCPInfo != nil {
 		// Convert to Mbps.
 		mbps = 8 * float64(m[len(m)-1].TCPInfo.BytesAcked) / float64(m[len(m)-1].TCPInfo.ElapsedTime)
 	}

ndt7/ndt7test/ndt7test.go

@@ -0,0 +1,41 @@
+package ndt7test
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/m-lab/go/testingx"
+	"github.com/m-lab/ndt-server/ndt7/handler"
+	"github.com/m-lab/ndt-server/ndt7/spec"
+	"github.com/m-lab/ndt-server/netx"
+)
+
+// NewNDT7Server creates a local httptest server capable of running an ndt7
+// measurement in unittests.
+func NewNDT7Server(t *testing.T) (*handler.Handler, *httptest.Server) {
+	dir, err := ioutil.TempDir("", "ndt7test-*")
+	testingx.Must(t, err, "failed to create temp dir")
+
+	// TODO: add support for token verifiers.
+	// TODO: add support for TLS server.
+	ndt7Handler := &handler.Handler{DataDir: dir}
+	ndt7Mux := http.NewServeMux()
+	ndt7Mux.Handle(spec.DownloadURLPath, http.HandlerFunc(ndt7Handler.Download))
+	ndt7Mux.Handle(spec.UploadURLPath, http.HandlerFunc(ndt7Handler.Upload))
+
+	// Create unstarted so we can setup a custom netx.Listener.
+	ts := httptest.NewUnstartedServer(ndt7Mux)
+	listener, err := net.Listen("tcp", ":0")
+	testingx.Must(t, err, "failed to allocate a listening tcp socket")
+	addr := (listener.(*net.TCPListener)).Addr().(*net.TCPAddr)
+	// Populate insecure port value with dynamic port.
+	ndt7Handler.InsecurePort = fmt.Sprintf(":%d", addr.Port)
+	ts.Listener = netx.NewListener(listener.(*net.TCPListener))
+	// Now that the test server has our custom listener, start it.
+	ts.Start()
+	return ndt7Handler, ts
+}

ndt7/ndt7test/ndt7test_test.go

@@ -0,0 +1,66 @@
+package ndt7test
+
+import (
+	"context"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/m-lab/go/testingx"
+	"github.com/m-lab/ndt-server/ndt7/spec"
+)
+
+func TestNewNDT7Server(t *testing.T) {
+	// Create the ndt7test server.
+	h, srv := NewNDT7Server(t)
+	defer os.RemoveAll(h.DataDir)
+
+	// Prepare to run a simplified download with ndt7test server.
+	URL, _ := url.Parse(srv.URL)
+	URL.Scheme = "ws"
+	URL.Path = spec.DownloadURLPath
+	headers := http.Header{}
+	headers.Add("Sec-WebSocket-Protocol", spec.SecWebSocketProtocol)
+	headers.Add("User-Agent", "fake-user-agent")
+	ctx := context.Background()
+	dialer := websocket.Dialer{HandshakeTimeout: 10 * time.Second}
+	conn, _, err := dialer.DialContext(ctx, URL.String(), headers)
+	testingx.Must(t, err, "failed to dial websocket ndt7 test")
+	err = simpleDownload(ctx, t, conn)
+	if err != nil && !websocket.IsCloseError(err, websocket.CloseNormalClosure) {
+		testingx.Must(t, err, "failed to download")
+	}
+
+	// Allow the server time to save the file, the client may stop before the server does.
+	time.Sleep(1 * time.Second)
+	// Verify a file was saved.
+	m, err := filepath.Glob(h.DataDir + "/ndt7/*/*/*/*")
+	testingx.Must(t, err, "failed to glob datadir: %s", h.DataDir)
+	if len(m) == 0 {
+		t.Errorf("no files found")
+	}
+}
+
+func simpleDownload(ctx context.Context, t *testing.T, conn *websocket.Conn) error {
+	defer conn.Close()
+	wholectx, cancel := context.WithTimeout(ctx, spec.MaxRuntime)
+	defer cancel()
+	conn.SetReadLimit(spec.MaxMessageSize)
+	err := conn.SetReadDeadline(time.Now().Add(spec.MaxRuntime))
+	testingx.Must(t, err, "failed to set read deadline")
+
+	var total int64
+	// WARNING: this is not a reference client.
+	for wholectx.Err() == nil {
+		_, mdata, err := conn.ReadMessage()
+		if err != nil {
+			return err
+		}
+		total += int64(len(mdata))
+	}
+	return nil
+}