merged with fixes

internal/store/redisstore/redis_test.go

@@ -0,0 +1,72 @@
+package redisstore
+
+import (
+	"context"
+	"net"
+	"testing"
+	"time"
+)
+
+func TestOpenBoundsStalledRedisPing(t *testing.T) {
+	address, stop := startStalledRedis(t)
+	defer stop()
+
+	started := time.Now()
+	client, err := open(context.Background(), address, "", 0, 50*time.Millisecond)
+	if client != nil {
+		_ = client.Close()
+	}
+	if err == nil {
+		t.Fatal("open() succeeded against a stalled Redis endpoint")
+	}
+	if elapsed := time.Since(started); elapsed > time.Second {
+		t.Fatalf("open() took %s, want at most 1s", elapsed)
+	}
+}
+
+func TestOpenPreservesEarlierCallerDeadline(t *testing.T) {
+	address, stop := startStalledRedis(t)
+	defer stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), 50*time.Millisecond)
+	defer cancel()
+	started := time.Now()
+	client, err := open(ctx, address, "", 0, time.Second)
+	if client != nil {
+		_ = client.Close()
+	}
+	if err == nil {
+		t.Fatal("open() succeeded against a stalled Redis endpoint")
+	}
+	if elapsed := time.Since(started); elapsed > time.Second {
+		t.Fatalf("open() took %s, want at most 1s", elapsed)
+	}
+}
+
+func startStalledRedis(t *testing.T) (string, func()) {
+	t.Helper()
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	if err != nil {
+		t.Fatalf("listen: %v", err)
+	}
+	stop := make(chan struct{})
+	done := make(chan struct{})
+	go func() {
+		defer close(done)
+		for {
+			conn, err := listener.Accept()
+			if err != nil {
+				return
+			}
+			go func() {
+				<-stop
+				_ = conn.Close()
+			}()
+		}
+	}()
+	return listener.Addr().String(), func() {
+		close(stop)
+		_ = listener.Close()
+		<-done
+	}
+}