test(x): mock StrategyFinder dialers in smart integration tests

x/smart/integrationtest/integration_test.go

@@ -12,31 +12,84 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build nettest
-// +build nettest
-
 package integrationtest
 
 import (
 	"bytes"
 	"context"
+	"errors"
+	"fmt"
 	"log"
+	"net"
+	"net/http/httptest"
 	"runtime"
 	"strings"
 	"testing"
 	"time"
 
-	"golang.getoutline.org/sdk/x/configurl"
+	"golang.getoutline.org/sdk/transport"
 	"golang.getoutline.org/sdk/x/smart"
 	"github.com/stretchr/testify/require"
 )
 
+// mockStreamDialer intercepts stream connections made by StrategyFinder.
+// It redirects connection attempts for specific badssl.com endpoints to local mock servers,
+// and fails all other connections to simulate a completely broken network environment.
+type mockStreamDialer struct {
+	base                     transport.StreamDialer
+	untrustedHTTPSServerAddr string // Address of the local mock HTTPS server representing mitm-software.badssl.com
+	captivePortalServerAddr  string // Address of the local mock TCP server representing captive-portal.badssl.com:443
+}
+
+func (d *mockStreamDialer) DialStream(ctx context.Context, addr string) (transport.StreamConn, error) {
+	if addr == "mitm-software.badssl.com:443" {
+		return d.base.DialStream(ctx, d.untrustedHTTPSServerAddr)
+	}
+	if addr == "captive-portal.badssl.com:443" {
+		return d.base.DialStream(ctx, d.captivePortalServerAddr)
+	}
+	return nil, errors.New("dial DNS resolver failed")
+}
+
+// errorPacketDialer simulates UDP dial failures by immediately returning an error.
+// This mocks broken DNS-over-UDP resolvers (like china.cn, ns1.tic.ir, tmcell.tm).
+type errorPacketDialer struct{}
+
+func (d *errorPacketDialer) DialPacket(ctx context.Context, addr string) (net.Conn, error) {
+	return nil, errors.New("dial DNS resolver failed")
+}
+
+// startMockCaptivePortalTCPServer starts a local TCP server that accepts and immediately closes connections.
+// This is used to mock a captive portal that interrupts TLS handshakes.
+func startMockCaptivePortalTCPServer(t *testing.T) string {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+	go func() {
+		for {
+			conn, err := listener.Accept()
+			if err != nil {
+				return
+			}
+			conn.Close()
+		}
+	}()
+	t.Cleanup(func() {
+		listener.Close()
+	})
+	return listener.Addr().String()
+}
+
 func Test_Integration_NewDialer_BrokenConfig(t *testing.T) {
 	if runtime.GOOS == "android" {
 		// See https://golang.getoutline.org/sdk/issues/504
 		t.Skip("Skip Smart Dialer integration test on Android until storage is made compatible with android emulator testing")
 	}
 
+	ts := httptest.NewTLSServer(nil)
+	t.Cleanup(ts.Close)
+
+	captivePortalAddr := startMockCaptivePortalTCPServer(t)
+
 	configBytes := []byte(`
 dns:
     # We get censored DNS responses when we send queries to an IP in China.
@@ -61,57 +114,50 @@ tls:
 fallback:
     # Nonexistent Outline Server
     - ss://Y2hhY2hhMjAtaWV0Zi1wb2x5MTMwNTprSzdEdHQ0MkJLOE9hRjBKYjdpWGFK@1.2.3.4:9999/?outline=1
-    # TODO(#513): Psiphon disabled: psiphon-tls is incompatible with Go 1.25.
-    # - psiphon: {
-    #     "PropagationChannelId":"ID1",
-    #     "SponsorId":"ID2",
-    #     "DisableLocalSocksProxy" : true,
-    #     "DisableLocalHTTPProxy" : true,
-    #     "EstablishTunnelTimeoutSeconds": 1,
-    #     }
+    - error: {
+        "error": "failed to start dialer"
+      }
     # Nonexistant local socks5 proxy
     - socks5://192.168.1.10:1080
 `)
 
 	testDomains := []string{"www.example.com", "example.com"}
-	transportType := ""
 
 	logBuffer := new(bytes.Buffer)
 	logger := log.New(logBuffer, "", log.LstdFlags)
 
-	providers := configurl.NewDefaultProviders()
-	packetDialer, err := providers.NewPacketDialer(context.Background(), transportType)
-	if err != nil {
-		require.NoError(t, err)
-	}
-	streamDialer, err := providers.NewStreamDialer(context.Background(), transportType)
-	if err != nil {
-		require.NoError(t, err)
-	}
-
 	finder := smart.StrategyFinder{
 		LogWriter:    logger.Writer(),
 		TestTimeout:  5 * time.Second,
-		StreamDialer: streamDialer,
-		PacketDialer: packetDialer,
+		StreamDialer: &mockStreamDialer{
+			base:                     &transport.TCPDialer{},
+			untrustedHTTPSServerAddr: ts.Listener.Addr().String(),
+			captivePortalServerAddr:  captivePortalAddr,
+		},
+		PacketDialer: &errorPacketDialer{},
 	}
-	// TODO(#513): Psiphon disabled: psiphon-tls is incompatible with Go 1.25.
-	// finder.RegisterFallbackParser("psiphon", psiphon.ParseConfig)
+	finder.RegisterFallbackParser("error", func(ctx context.Context, config smart.YAMLNode) (transport.StreamDialer, string, error) {
+		m, ok := config.(map[string]any)
+		if !ok {
+			return nil, "", fmt.Errorf("invalid config of type %T", config)
+		}
+		errStr, _ := m["error"].(string)
+		return nil, "signature_placeholder", errors.New(errStr)
+	})
 
-	_, err = finder.NewDialer(context.Background(), testDomains, configBytes)
+	_, err := finder.NewDialer(context.Background(), testDomains, configBytes)
 
 	require.Error(t, err)
 	require.Contains(t, err.Error(), "could not find a working fallback: all tests failed")
 
 	// Check the content of the log writer.
-	// Different systems have different network error messages,
-	// so we only check the broad strokes.
+	// Different systems have different network error messages, so we only check the broad strokes.
 	expectedLogs := []string{
 		"request for A query failed: dial DNS resolver failed:",
 		`request for A query failed: receive DNS message failed: failed to get HTTP response: Post "https://mitm-software.badssl.com:443/dns-query": tls:`,
 		"🏃 running test: 'ss://Y2hhY2hhMjAtaWV0Zi1wb2x5MTMwNTprSzdEdHQ0MkJLOE9hRjBKYjdpWGFK@1.2.3.4:9999/?outline=1'",
-		// TODO(#513): Psiphon disabled: psiphon-tls is incompatible with Go 1.25.
-		// "❌ Failed to create fallback[1]: [{psiphon: {DisableLocalHTTPProxy: true, DisableLocalSocksProxy: true, Establish…]: failed to start psiphon dialer: clientlib: tunnel establishment timeout",
+		"❌ Failed to create fallback[1]:",
+		"failed to start dialer",
 		"🏃 running test: 'socks5://192.168.1.10:1080' (domain: www.example.com.)",
 	}
 	logContent := logBuffer.String()