{channel,server}_test: add tests for message limits.

Adjust unit test to accomodate for altered internal interfaces.
Add unit tests to exercise the new message size limit options.

Signed-off-by: Krisztian Litkey <[email protected]>

Author: klihub

channel_test.go

@@ -31,8 +31,8 @@ import (
 func TestReadWriteMessage(t *testing.T) {
 	var (
 		w, r     = net.Pipe()
-		ch       = newChannel(w)
-		rch      = newChannel(r)
+		ch       = newChannel(w, 0)
+		rch      = newChannel(r, 0)
 		messages = [][]byte{
 			[]byte("hello"),
 			[]byte("this is a test"),
@@ -90,7 +90,7 @@ func TestReadWriteMessage(t *testing.T) {
 func TestMessageOversize(t *testing.T) {
 	var (
 		w, _ = net.Pipe()
-		wch  = newChannel(w)
+		wch  = newChannel(w, 0)
 		msg  = bytes.Repeat([]byte("a message of massive length"), 512<<10)
 		errs = make(chan error, 1)
 	)

server_test.go

@@ -19,6 +19,7 @@ package ttrpc
 import (
 	"bytes"
 	"context"
+	"crypto/md5"
 	"errors"
 	"fmt"
 	"net"
@@ -61,10 +62,17 @@ func (tc *testingClient) Test(ctx context.Context, req *internal.TestPayload) (*
 }
 
 // testingServer is what would be implemented by the user of this package.
-type testingServer struct{}
+type testingServer struct {
+	echoOnce bool
+}
 
 func (s *testingServer) Test(ctx context.Context, req *internal.TestPayload) (*internal.TestPayload, error) {
-	tp := &internal.TestPayload{Foo: strings.Repeat(req.Foo, 2)}
+	tp := &internal.TestPayload{}
+	if s.echoOnce {
+		tp.Foo = req.Foo
+	} else {
+		tp.Foo = strings.Repeat(req.Foo, 2)
+	}
 	if dl, ok := ctx.Deadline(); ok {
 		tp.Deadline = dl.UnixNano()
 	}
@@ -299,38 +307,155 @@ func TestServerClose(t *testing.T) {
 }
 
 func TestOversizeCall(t *testing.T) {
-	var (
-		ctx             = context.Background()
-		server          = mustServer(t)(NewServer())
-		addr, listener  = newTestListener(t)
-		errs            = make(chan error, 1)
-		client, cleanup = newTestClient(t, addr)
-	)
-	defer cleanup()
-	defer listener.Close()
-	go func() {
-		errs <- server.Serve(ctx, listener)
-	}()
+	type testCase struct {
+		name        string
+		echoOnce    bool
+		clientLimit int
+		serverLimit int
+		requestSize int
+		clientFail  bool
+		serverFail  bool
+	}
+
+	overhead := getWireMessageOverhead(t)
+
+	runTest := func(t *testing.T, tc *testCase) {
+		var (
+			ctx             = context.Background()
+			server          = mustServer(t)(NewServer(WithServerWireMessageLimit(tc.serverLimit)))
+			addr, listener  = newTestListener(t)
+			errs            = make(chan error, 1)
+			client, cleanup = newTestClient(t, addr, WithClientWireMessageLimit(tc.clientLimit))
+		)
+		defer cleanup()
+		defer listener.Close()
+		go func() {
+			errs <- server.Serve(ctx, listener)
+		}()
+
+		registerTestingService(server, &testingServer{echoOnce: tc.echoOnce})
+
+		req := &internal.TestPayload{
+			Foo: strings.Repeat("a", tc.requestSize),
+		}
+		rsp := &internal.TestPayload{}
+
+		err := client.Call(ctx, serviceName, "Test", req, rsp)
+		if tc.clientFail {
+			if err == nil {
+				t.Fatalf("expected error from oversized message")
+			} else if status, ok := status.FromError(err); !ok {
+				t.Fatalf("expected status present in error: %v", err)
+			} else if status.Code() != codes.ResourceExhausted {
+				t.Fatalf("expected code: %v != %v", status.Code(), codes.ResourceExhausted)
+			}
+		} else if tc.serverFail {
+			if err == nil {
+				t.Fatalf("expected error from server-side oversized message")
+			}
+		} else {
+			if err != nil {
+				t.Fatalf("expected success, got error %v", err)
+			}
+		}
 
-	registerTestingService(server, &testingServer{})
+		if err := server.Shutdown(ctx); err != nil {
+			t.Fatal(err)
+		}
+		if err := <-errs; err != ErrServerClosed {
+			t.Fatal(err)
+		}
+	}
 
-	tp := &internal.TestPayload{
-		Foo: strings.Repeat("a", 1+messageLengthMax),
+	for _, tc := range []*testCase{
+		{
+			name:        "default limits, fitting request and response",
+			echoOnce:    true,
+			clientLimit: 0,
+			serverLimit: 0,
+			requestSize: DefaultMessageLengthLimit - overhead,
+		},
+		{
+			name:        "default limits, oversized request",
+			echoOnce:    true,
+			clientLimit: 0,
+			serverLimit: 0,
+			requestSize: DefaultMessageLengthLimit,
+			clientFail:  true,
+		},
+		{
+			name:        "default limits, oversized response",
+			clientLimit: 0,
+			serverLimit: 0,
+			requestSize: DefaultMessageLengthLimit / 2,
+			serverFail:  true,
+		},
+		{
+			name:        "8K limits, fitting 4K request and response",
+			echoOnce:    true,
+			clientLimit: 8 * 1024,
+			serverLimit: 8 * 1024,
+			requestSize: 4 * 1024,
+		},
+		{
+			name:        "8K limits, fitting cc. 4K request and response",
+			echoOnce:    true,
+			clientLimit: 4 * 1024,
+			serverLimit: 4 * 1024,
+			requestSize: 4*1024 - overhead,
+		},
+		{
+			name:        "4K limits, non-fitting 4K response",
+			echoOnce:    true,
+			clientLimit: 4*1024 + overhead,
+			serverLimit: 4 * 1024,
+			requestSize: 4 * 1024,
+			serverFail:  true,
+		},
+		{
+			name:        "too small limits, adjusted to minimum accepted limit",
+			echoOnce:    true,
+			clientLimit: 4,
+			serverLimit: 4,
+			requestSize: 4*1024 - overhead,
+		},
+		{
+			name:        "maximum allowed protocol limit",
+			echoOnce:    true,
+			clientLimit: MaxMessageLengthLimit,
+			serverLimit: MaxMessageLengthLimit,
+			requestSize: MaxMessageLengthLimit - overhead,
+		},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			runTest(t, tc)
+		})
 	}
-	if err := client.Call(ctx, serviceName, "Test", tp, tp); err == nil {
-		t.Fatalf("expected error from oversized message")
-	} else if status, ok := status.FromError(err); !ok {
-		t.Fatalf("expected status present in error: %v", err)
-	} else if status.Code() != codes.ResourceExhausted {
-		t.Fatalf("expected code: %v != %v", status.Code(), codes.ResourceExhausted)
+}
+
+func getWireMessageOverhead(t *testing.T) int {
+	emptyReq, err := codec{}.Marshal(&Request{
+		Service: serviceName,
+		Method:  "Test",
+	})
+	if err != nil {
+		t.Fatalf("failed to marshal empty request: %v", err)
 	}
 
-	if err := server.Shutdown(ctx); err != nil {
-		t.Fatal(err)
+	emptyRsp, err := codec{}.Marshal(&Response{
+		Status: status.New(codes.OK, "").Proto(),
+	})
+	if err != nil {
+		t.Fatalf("failed to marshal empty response: %v", err)
 	}
-	if err := <-errs; err != ErrServerClosed {
-		t.Fatal(err)
+
+	reqLen := len(emptyReq)
+	rspLen := len(emptyRsp)
+	if reqLen > rspLen {
+		return reqLen + messageHeaderLength
 	}
+
+	return rspLen + messageHeaderLength
 }
 
 func TestClientEOF(t *testing.T) {
@@ -551,13 +676,20 @@ func newTestClient(t testing.TB, addr string, opts ...ClientOpts) (*Client, func
 }
 
 func newTestListener(t testing.TB) (string, net.Listener) {
-	var prefix string
+	var (
+		name   = t.Name()
+		prefix string
+	)
 
 	// Abstracts sockets are only available on Linux.
 	if runtime.GOOS == "linux" {
 		prefix = "\x00"
+	} else {
+		if split := strings.SplitN(name, "/", 2); len(split) == 2 {
+			name = split[0] + "-" + fmt.Sprintf("%x", md5.Sum([]byte(split[1])))
+		}
 	}
-	addr := prefix + t.Name()
+	addr := prefix + name
 	listener, err := net.Listen("unix", addr)
 	if err != nil {
 		t.Fatal(err)