Merge branch 'tests'

3 files changed, 1001 insertions, 0 deletions

diff --git a/testingTools.go b/testingTools.go
new file mode 100644
index 0000000..2f73031
--- /dev/null
+++ b/testingTools.go
@@ -0,0 +1,426 @@
+package xgb
+
+import (
+	"bytes"
+	"errors"
+	"io"
+	"net"
+	"regexp"
+	"runtime"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+)
+
+// Leaks monitor
+
+type goroutine struct {
+	id    int
+	name  string
+	stack []byte
+}
+
+type leaks struct {
+	name       string
+	goroutines map[int]goroutine
+	report     []*leaks
+}
+
+func leaksMonitor(name string, monitors ...*leaks) *leaks {
+	return &leaks{
+		name,
+		leaks{}.collectGoroutines(),
+		monitors,
+	}
+}
+
+// ispired by https://golang.org/src/runtime/debug/stack.go?s=587:606#L21
+// stack returns a formatted stack trace of all goroutines.
+// It calls runtime.Stack with a large enough buffer to capture the entire trace.
+func (_ leaks) stack() []byte {
+	buf := make([]byte, 1024)
+	for {
+		n := runtime.Stack(buf, true)
+		if n < len(buf) {
+			return buf[:n]
+		}
+		buf = make([]byte, 2*len(buf))
+	}
+}
+
+func (l leaks) collectGoroutines() map[int]goroutine {
+	res := make(map[int]goroutine)
+	stacks := bytes.Split(l.stack(), []byte{'\n', '\n'})
+
+	regexpId := regexp.MustCompile(`^\s*goroutine\s*(\d+)`)
+	for _, st := range stacks {
+		lines := bytes.Split(st, []byte{'\n'})
+		if len(lines) < 2 {
+			panic("routine stach has less tnan two lines: " + string(st))
+		}
+
+		idMatches := regexpId.FindSubmatch(lines[0])
+		if len(idMatches) < 2 {
+			panic("no id found in goroutine stack's first line: " + string(lines[0]))
+		}
+		id, err := strconv.Atoi(string(idMatches[1]))
+		if err != nil {
+			panic("converting goroutine id to number error: " + err.Error())
+		}
+		if _, ok := res[id]; ok {
+			panic("2 goroutines with same id: " + strconv.Itoa(id))
+		}
+		name := strings.TrimSpace(string(lines[1]))
+
+		//filter out our stack routine
+		if strings.Contains(name, "xgb.leaks.stack") {
+			continue
+		}
+
+		res[id] = goroutine{id, name, st}
+	}
+	return res
+}
+
+func (l leaks) leakingGoroutines() []goroutine {
+	goroutines := l.collectGoroutines()
+	res := []goroutine{}
+	for id, gr := range goroutines {
+		if _, ok := l.goroutines[id]; ok {
+			continue
+		}
+		res = append(res, gr)
+	}
+	return res
+}
+func (l leaks) checkTesting(t *testing.T) {
+	if len(l.leakingGoroutines()) == 0 {
+		return
+	}
+	leakTimeout := 10 * time.Millisecond
+	time.Sleep(leakTimeout)
+	//t.Logf("possible goroutine leakage, waiting %v", leakTimeout)
+	grs := l.leakingGoroutines()
+	for _, gr := range grs {
+		t.Errorf("%s: %s is leaking", l.name, gr.name)
+		//t.Errorf("%s: %s is leaking\n%v", l.name, gr.name, string(gr.stack))
+	}
+	for _, rl := range l.report {
+		rl.ignoreLeak(grs...)
+	}
+}
+func (l *leaks) ignoreLeak(grs ...goroutine) {
+	for _, gr := range grs {
+		l.goroutines[gr.id] = gr
+	}
+}
+
+// dummy net.Conn
+
+type dAddr struct {
+	s string
+}
+
+func (_ dAddr) Network() string { return "dummy" }
+func (a dAddr) String() string  { return a.s }
+
+var (
+	dNCErrNotImplemented = errors.New("command not implemented")
+	dNCErrClosed         = errors.New("server closed")
+	dNCErrWrite          = errors.New("server write failed")
+	dNCErrRead           = errors.New("server read failed")
+	dNCErrResponse       = errors.New("server response error")
+)
+
+type dNCIoResult struct {
+	n   int
+	err error
+}
+type dNCIo struct {
+	b      []byte
+	result chan dNCIoResult
+}
+
+type dNCCWriteLock struct{}
+type dNCCWriteUnlock struct{}
+type dNCCWriteError struct{}
+type dNCCWriteSuccess struct{}
+type dNCCReadLock struct{}
+type dNCCReadUnlock struct{}
+type dNCCReadError struct{}
+type dNCCReadSuccess struct{}
+
+// dummy net.Conn interface. Needs to be constructed via newDummyNetConn([...]) function.
+type dNC struct {
+	reply   func([]byte) []byte
+	addr    dAddr
+	in, out chan dNCIo
+	control chan interface{}
+	done    chan struct{}
+}
+
+// Results running dummy server, satisfying net.Conn interface for test purposes.
+// 'name' parameter will be returned via (*dNC).Local/RemoteAddr().String()
+// 'reply' parameter function will be runned only on successful (*dNC).Write(b) with 'b' as parameter to 'reply'. The result will be stored in internal buffer and can be retrieved later via (*dNC).Read([...]) method.
+// It is users responsibility to stop and clean up resources with (*dNC).Close, if not needed anymore.
+// By default, the (*dNC).Write([...]) and (*dNC).Read([...]) methods are unlocked and will not result in error.
+//TODO make (*dNC).SetDeadline, (*dNC).SetReadDeadline, (*dNC).SetWriteDeadline work proprely.
+func newDummyNetConn(name string, reply func([]byte) []byte) *dNC {
+
+	s := &dNC{
+		reply,
+		dAddr{name},
+		make(chan dNCIo), make(chan dNCIo),
+		make(chan interface{}),
+		make(chan struct{}),
+	}
+
+	in, out := s.in, chan dNCIo(nil)
+	buf := &bytes.Buffer{}
+	errorRead, errorWrite := false, false
+	lockRead := false
+
+	go func() {
+		defer close(s.done)
+		for {
+			select {
+			case dxsio := <-in:
+				if errorWrite {
+					dxsio.result <- dNCIoResult{0, dNCErrWrite}
+					break
+				}
+
+				response := s.reply(dxsio.b)
+
+				buf.Write(response)
+				dxsio.result <- dNCIoResult{len(dxsio.b), nil}
+
+				if !lockRead && buf.Len() > 0 && out == nil {
+					out = s.out
+				}
+			case dxsio := <-out:
+				if errorRead {
+					dxsio.result <- dNCIoResult{0, dNCErrRead}
+					break
+				}
+
+				n, err := buf.Read(dxsio.b)
+				dxsio.result <- dNCIoResult{n, err}
+
+				if buf.Len() == 0 {
+					out = nil
+				}
+			case ci := <-s.control:
+				if ci == nil {
+					return
+				}
+				switch ci.(type) {
+				case dNCCWriteLock:
+					in = nil
+				case dNCCWriteUnlock:
+					in = s.in
+				case dNCCWriteError:
+					errorWrite = true
+				case dNCCWriteSuccess:
+					errorWrite = false
+				case dNCCReadLock:
+					out = nil
+					lockRead = true
+				case dNCCReadUnlock:
+					lockRead = false
+					if buf.Len() > 0 && out == nil {
+						out = s.out
+					}
+				case dNCCReadError:
+					errorRead = true
+				case dNCCReadSuccess:
+					errorRead = false
+				default:
+				}
+			}
+		}
+	}()
+	return s
+}
+
+// Shuts down dummy net.Conn server. Every blocking or future method calls will do nothing and result in error.
+// Result will be dNCErrClosed if server was allready closed.
+// Server can not be unclosed.
+func (s *dNC) Close() error {
+	select {
+	case s.control <- nil:
+		<-s.done
+		return nil
+	case <-s.done:
+	}
+	return dNCErrClosed
+}
+
+// Performs a write action to server.
+// If not locked by (*dNC).WriteLock, it results in error or success. If locked, this method will block until unlocked, or closed.
+//
+// This method can be set to result in error or success, via (*dNC).WriteError() or (*dNC).WriteSuccess() methods.
+//
+// If setted to result in error, the 'reply' function will NOT be called and internal buffer will NOT increasethe.
+// Result will be (0, dNCErrWrite).
+//
+// If setted to result in success, the 'reply' function will be called and its result will be writen to internal buffer.
+// If there is something in the internal buffer, the (*dNC).Read([...]) will be unblocked (if not previously locked with (*dNC).ReadLock).
+// Result will be (len(b), nil)
+//
+// If server was closed previously, result will be (0, dNCErrClosed).
+func (s *dNC) Write(b []byte) (int, error) {
+	resChan := make(chan dNCIoResult)
+	select {
+	case s.in <- dNCIo{b, resChan}:
+		res := <-resChan
+		return res.n, res.err
+	case <-s.done:
+	}
+	return 0, dNCErrClosed
+}
+
+// Performs a read action from server.
+// If locked by (*dNC).ReadLock(), this method will block until unlocked with (*dNC).ReadUnlock(), or server closes.
+//
+// If not locked, this method can be setted to result imidiatly in error, will block if internal buffer is empty or will perform an read operation from internal buffer.
+//
+// If setted to result in error via (*dNC).ReadError(), the result will be (0, dNCErrWrite).
+//
+// If not locked and not setted to result in error via (*dNC).ReadSuccess(), this method will block until internall buffer is not empty, than it returns the result of the buffer read operation via (*bytes.Buffer).Read([...]).
+// If the internal buffer is empty after this method, all follwing (*dNC).Read([...]), requests will block until internall buffer is filled after successful write requests.
+//
+// If server was closed previously, result will be (0, io.EOF).
+func (s *dNC) Read(b []byte) (int, error) {
+	resChan := make(chan dNCIoResult)
+	select {
+	case s.out <- dNCIo{b, resChan}:
+		res := <-resChan
+		return res.n, res.err
+	case <-s.done:
+	}
+	return 0, io.EOF
+}
+func (s *dNC) LocalAddr() net.Addr                { return s.addr }
+func (s *dNC) RemoteAddr() net.Addr               { return s.addr }
+func (s *dNC) SetDeadline(t time.Time) error      { return dNCErrNotImplemented }
+func (s *dNC) SetReadDeadline(t time.Time) error  { return dNCErrNotImplemented }
+func (s *dNC) SetWriteDeadline(t time.Time) error { return dNCErrNotImplemented }
+
+func (s *dNC) Control(i interface{}) error {
+	select {
+	case s.control <- i:
+		return nil
+	case <-s.done:
+	}
+	return dNCErrClosed
+}
+
+// Locks writing. All write requests will be blocked until write is unlocked with (*dNC).WriteUnlock, or server closes.
+func (s *dNC) WriteLock() error {
+	return s.Control(dNCCWriteLock{})
+}
+
+// Unlocks writing. All blocked write requests until now will be accepted.
+func (s *dNC) WriteUnlock() error {
+	return s.Control(dNCCWriteUnlock{})
+}
+
+// Unlocks writing and makes (*dNC).Write to result (0, dNCErrWrite).
+func (s *dNC) WriteError() error {
+	if err := s.WriteUnlock(); err != nil {
+		return err
+	}
+	return s.Control(dNCCWriteError{})
+}
+
+// Unlocks writing and makes (*dNC).Write([...]) not result in error. See (*dNC).Write for details.
+func (s *dNC) WriteSuccess() error {
+	if err := s.WriteUnlock(); err != nil {
+		return err
+	}
+	return s.Control(dNCCWriteSuccess{})
+}
+
+// Locks reading. All read requests will be blocked until read is unlocked with (*dNC).ReadUnlock, or server closes.
+// (*dNC).Read([...]) wil block even after successful write.
+func (s *dNC) ReadLock() error {
+	return s.Control(dNCCReadLock{})
+}
+
+// Unlocks reading. If the internall buffer is not empty, next read will not block.
+func (s *dNC) ReadUnlock() error {
+	return s.Control(dNCCReadUnlock{})
+}
+
+// Unlocks read and makes every blocked and following (*dNC).Read([...]) imidiatly result in error. See (*dNC).Read for details.
+func (s *dNC) ReadError() error {
+	if err := s.ReadUnlock(); err != nil {
+		return err
+	}
+	return s.Control(dNCCReadError{})
+}
+
+// Unlocks read and makes every blocked and following (*dNC).Read([...]) requests be handled, if according to internal buffer. See (*dNC).Read for details.
+func (s *dNC) ReadSuccess() error {
+	if err := s.ReadUnlock(); err != nil {
+		return err
+	}
+	return s.Control(dNCCReadSuccess{})
+}
+
+// dummy X server replier for dummy net.Conn
+
+type dXSEvent struct{}
+
+func (_ dXSEvent) Bytes() []byte  { return nil }
+func (_ dXSEvent) String() string { return "dummy X server event" }
+
+type dXSError struct {
+	seqId uint16
+}
+
+func (e dXSError) SequenceId() uint16 { return e.seqId }
+func (_ dXSError) BadId() uint32      { return 0 }
+func (_ dXSError) Error() string      { return "dummy X server error reply" }
+
+func newDummyXServerReplier() func([]byte) []byte {
+	// register xgb error & event replies
+	NewErrorFuncs[255] = func(buf []byte) Error {
+		return dXSError{Get16(buf[2:])}
+	}
+	NewEventFuncs[128&127] = func(buf []byte) Event {
+		return dXSEvent{}
+	}
+
+	// sequence number generator
+	seqId := uint16(1)
+	incrementSequenceId := func() {
+		// this has to be the same algorithm as in (*Conn).generateSeqIds
+		if seqId == uint16((1<<16)-1) {
+			seqId = 0
+		} else {
+			seqId++
+		}
+	}
+	return func(request []byte) []byte {
+		res := make([]byte, 32)
+		switch string(request) {
+		case "event":
+			res[0] = 128
+			return res
+		case "error":
+			res[0] = 0   // error
+			res[1] = 255 // error function
+		default:
+			res[0] = 1 // reply
+		}
+		Put16(res[2:], seqId) // sequence number
+		incrementSequenceId()
+		if string(request) == "noreply" {
+			return nil
+		}
+		return res
+	}
+}
diff --git a/testingTools_test.go b/testingTools_test.go
new file mode 100644
index 0000000..518b326
--- /dev/null
+++ b/testingTools_test.go
@@ -0,0 +1,350 @@
+package xgb
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"sync"
+	"testing"
+	"time"
+)
+
+func TestLeaks(t *testing.T) {
+	lm := leaksMonitor("lm")
+	if lgrs := lm.leakingGoroutines(); len(lgrs) != 0 {
+		t.Errorf("leakingGoroutines returned %d leaking goroutines, want 0", len(lgrs))
+	}
+
+	done := make(chan struct{})
+	wg := &sync.WaitGroup{}
+
+	wg.Add(1)
+	go func() {
+		<-done
+		wg.Done()
+	}()
+
+	if lgrs := lm.leakingGoroutines(); len(lgrs) != 1 {
+		t.Errorf("leakingGoroutines returned %d leaking goroutines, want 1", len(lgrs))
+	}
+
+	wg.Add(1)
+	go func() {
+		<-done
+		wg.Done()
+	}()
+
+	if lgrs := lm.leakingGoroutines(); len(lgrs) != 2 {
+		t.Errorf("leakingGoroutines returned %d leaking goroutines, want 2", len(lgrs))
+	}
+
+	close(done)
+	wg.Wait()
+
+	if lgrs := lm.leakingGoroutines(); len(lgrs) != 0 {
+		t.Errorf("leakingGoroutines returned %d leaking goroutines, want 0", len(lgrs))
+	}
+
+	lm.checkTesting(t)
+	//TODO multiple leak monitors with report ignore tests
+}
+
+func TestDummyNetConn(t *testing.T) {
+	ioStatesPairGenerator := func(writeStates, readStates []string) []func() (*dNC, error) {
+		writeSetters := map[string]func(*dNC) error{
+			"lock":    (*dNC).WriteLock,
+			"error":   (*dNC).WriteError,
+			"success": (*dNC).WriteSuccess,
+		}
+		readSetters := map[string]func(*dNC) error{
+			"lock":    (*dNC).ReadLock,
+			"error":   (*dNC).ReadError,
+			"success": (*dNC).ReadSuccess,
+		}
+
+		res := []func() (*dNC, error){}
+		for _, writeState := range writeStates {
+			writeState, writeSetter := writeState, writeSetters[writeState]
+			if writeSetter == nil {
+				panic("unknown write state: " + writeState)
+				continue
+			}
+			for _, readState := range readStates {
+				readState, readSetter := readState, readSetters[readState]
+				if readSetter == nil {
+					panic("unknown read state: " + readState)
+					continue
+				}
+				res = append(res, func() (*dNC, error) {
+
+					// loopback server
+					s := newDummyNetConn("w:"+writeState+";r:"+readState, func(b []byte) []byte { return b })
+
+					if err := readSetter(s); err != nil {
+						s.Close()
+						return nil, errors.New("set read " + readState + " error: " + err.Error())
+					}
+
+					if err := writeSetter(s); err != nil {
+						s.Close()
+						return nil, errors.New("set write " + writeState + " error: " + err.Error())
+					}
+
+					return s, nil
+				})
+			}
+		}
+		return res
+	}
+
+	timeout := 10 * time.Millisecond
+	wantResponse := func(action func(*dNC) error, want, block error) func(*dNC) error {
+		return func(s *dNC) error {
+			actionResult := make(chan error)
+			timedOut := make(chan struct{})
+			go func() {
+				err := action(s)
+				select {
+				case <-timedOut:
+					if err != block {
+						t.Errorf("after unblocking, action result=%v, want %v", err, block)
+					}
+				case actionResult <- err:
+				}
+			}()
+			select {
+			case err := <-actionResult:
+				if err != want {
+					return errors.New(fmt.Sprintf("action result=%v, want %v", err, want))
+				}
+			case <-time.After(timeout):
+				close(timedOut)
+				return errors.New(fmt.Sprintf("action did not respond for %v, result want %v", timeout, want))
+			}
+			return nil
+		}
+	}
+	wantBlock := func(action func(*dNC) error, unblock error) func(*dNC) error {
+		return func(s *dNC) error {
+			actionResult := make(chan error)
+			timedOut := make(chan struct{})
+			go func() {
+				err := action(s)
+				select {
+				case <-timedOut:
+					if err != unblock {
+						t.Errorf("after unblocking, action result=%v, want %v", err, unblock)
+					}
+				case actionResult <- err:
+				}
+			}()
+			select {
+			case err := <-actionResult:
+				return errors.New(fmt.Sprintf("action result=%v, want to be blocked", err))
+			case <-time.After(timeout):
+				close(timedOut)
+			}
+			return nil
+		}
+	}
+	write := func(b string) func(*dNC) error {
+		return func(s *dNC) error {
+			n, err := s.Write([]byte(b))
+			if err == nil && n != len(b) {
+				return errors.New("Write returned nil error, but not everything was written")
+			}
+			return err
+		}
+	}
+	read := func(b string) func(*dNC) error {
+		return func(s *dNC) error {
+			r := make([]byte, len(b))
+			n, err := s.Read(r)
+			if err == nil {
+				if n != len(b) {
+					return errors.New("Read returned nil error, but not everything was read")
+				}
+				if !reflect.DeepEqual(r, []byte(b)) {
+					return errors.New("Read=\"" + string(r) + "\", want \"" + string(b) + "\"")
+				}
+			}
+			return err
+		}
+	}
+
+	testCases := []struct {
+		description string
+		servers     []func() (*dNC, error)
+		actions     []func(*dNC) error // actions per server
+	}{
+		{"close,close",
+			ioStatesPairGenerator(
+				[]string{"lock", "error", "success"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantResponse((*dNC).Close, nil, dNCErrClosed),
+				wantResponse((*dNC).Close, dNCErrClosed, dNCErrClosed),
+			},
+		},
+		{"write,close,write",
+			ioStatesPairGenerator(
+				[]string{"lock"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantBlock(write(""), dNCErrClosed),
+				wantResponse((*dNC).Close, nil, dNCErrClosed),
+				wantResponse(write(""), dNCErrClosed, dNCErrClosed),
+			},
+		},
+		{"write,close,write",
+			ioStatesPairGenerator(
+				[]string{"error"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write(""), dNCErrWrite, dNCErrClosed),
+				wantResponse((*dNC).Close, nil, dNCErrClosed),
+				wantResponse(write(""), dNCErrClosed, dNCErrClosed),
+			},
+		},
+		{"write,close,write",
+			ioStatesPairGenerator(
+				[]string{"success"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write(""), nil, dNCErrClosed),
+				wantResponse((*dNC).Close, nil, dNCErrClosed),
+				wantResponse(write(""), dNCErrClosed, dNCErrClosed),
+			},
+		},
+		{"read,close,read",
+			ioStatesPairGenerator(
+				[]string{"lock", "error", "success"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantBlock(read(""), io.EOF),
+				wantResponse((*dNC).Close, nil, dNCErrClosed),
+				wantResponse(read(""), io.EOF, io.EOF),
+			},
+		},
+		{"write,read",
+			ioStatesPairGenerator(
+				[]string{"lock"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantBlock(write("1"), dNCErrClosed),
+				wantBlock(read("1"), io.EOF),
+			},
+		},
+		{"write,read",
+			ioStatesPairGenerator(
+				[]string{"error"},
+				[]string{"lock", "error", "success"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write("1"), dNCErrWrite, dNCErrClosed),
+				wantBlock(read("1"), io.EOF),
+			},
+		},
+		{"write,read",
+			ioStatesPairGenerator(
+				[]string{"success"},
+				[]string{"lock"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write("1"), nil, dNCErrClosed),
+				wantBlock(read("1"), io.EOF),
+			},
+		},
+		{"write,read",
+			ioStatesPairGenerator(
+				[]string{"success"},
+				[]string{"error"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write("1"), nil, dNCErrClosed),
+				wantResponse(read("1"), dNCErrRead, io.EOF),
+			},
+		},
+		{"write,read",
+			ioStatesPairGenerator(
+				[]string{"success"},
+				[]string{"success"},
+			),
+			[]func(*dNC) error{
+				wantResponse(write("1"), nil, dNCErrClosed),
+				wantResponse(read("1"), nil, io.EOF),
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			defer leaksMonitor(tc.description).checkTesting(t)
+
+			for _, server := range tc.servers {
+				s, err := server()
+				if err != nil {
+					t.Error(err)
+					continue
+				}
+				if s == nil {
+					t.Error("nil server in testcase")
+					continue
+				}
+
+				t.Run(s.LocalAddr().String(), func(t *testing.T) {
+					defer leaksMonitor(s.LocalAddr().String()).checkTesting(t)
+					for _, action := range tc.actions {
+						if err := action(s); err != nil {
+							t.Error(err)
+							break
+						}
+					}
+					s.Close()
+				})
+			}
+		})
+	}
+}
+
+func TestDummyXServerReplier(t *testing.T) {
+	testCases := [][][2][]byte{
+		{
+			[2][]byte{[]byte("reply"), []byte{1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("eply"), []byte{1, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("ply"), []byte{1, 0, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("event"), []byte{128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("ly"), []byte{1, 0, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("y"), []byte{1, 0, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte(""), []byte{1, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("event"), []byte{128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("reply"), []byte{1, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("error"), []byte{0, 255, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("ply"), []byte{1, 0, 9, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("event"), []byte{128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("ly"), []byte{1, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("noreply"), nil},
+			[2][]byte{[]byte("error"), []byte{0, 255, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+			[2][]byte{[]byte("noreply"), nil},
+			[2][]byte{[]byte(""), []byte{1, 0, 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
+		},
+	}
+
+	for tci, tc := range testCases {
+		replier := newDummyXServerReplier()
+		for ai, ioPair := range tc {
+			in, want := ioPair[0], ioPair[1]
+			if out := replier(in); !bytes.Equal(out, want) {
+				t.Errorf("testCase %d, action %d, replier(%s) = %v, want %v", tci, ai, string(in), out, want)
+				break
+			}
+		}
+	}
+}
diff --git a/xgb_test.go b/xgb_test.go
new file mode 100644
index 0000000..19ed307
--- /dev/null
+++ b/xgb_test.go
@@ -0,0 +1,225 @@
+package xgb
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+	"time"
+)
+
+func TestConnOnNonBlockingDummyXServer(t *testing.T) {
+	timeout := 10 * time.Millisecond
+	checkedReply := func(wantError bool) func(*Conn) error {
+		request := "reply"
+		if wantError {
+			request = "error"
+		}
+		return func(c *Conn) error {
+			cookie := c.NewCookie(true, true)
+			c.NewRequest([]byte(request), cookie)
+			_, err := cookie.Reply()
+			if wantError && err == nil {
+				return errors.New(fmt.Sprintf("checked request \"%v\" with reply resulted in nil error, want some error", request))
+			}
+			if !wantError && err != nil {
+				return errors.New(fmt.Sprintf("checked request \"%v\" with reply resulted in error %v, want nil error", request, err))
+			}
+			return nil
+		}
+	}
+	checkedNoreply := func(wantError bool) func(*Conn) error {
+		request := "noreply"
+		if wantError {
+			request = "error"
+		}
+		return func(c *Conn) error {
+			cookie := c.NewCookie(true, false)
+			c.NewRequest([]byte(request), cookie)
+			err := cookie.Check()
+			if wantError && err == nil {
+				return errors.New(fmt.Sprintf("checked request \"%v\" with no reply resulted in nil error, want some error", request))
+			}
+			if !wantError && err != nil {
+				return errors.New(fmt.Sprintf("checked request \"%v\" with no reply resulted in error %v, want nil error", request, err))
+			}
+			return nil
+		}
+	}
+	uncheckedReply := func(wantError bool) func(*Conn) error {
+		request := "reply"
+		if wantError {
+			request = "error"
+		}
+		return func(c *Conn) error {
+			cookie := c.NewCookie(false, true)
+			c.NewRequest([]byte(request), cookie)
+			_, err := cookie.Reply()
+			if err != nil {
+				return errors.New(fmt.Sprintf("unchecked request \"%v\" with reply resulted in %v, want nil", request, err))
+			}
+			return nil
+		}
+	}
+	uncheckedNoreply := func(wantError bool) func(*Conn) error {
+		request := "noreply"
+		if wantError {
+			request = "error"
+		}
+		return func(c *Conn) error {
+			cookie := c.NewCookie(false, false)
+			c.NewRequest([]byte(request), cookie)
+			return nil
+		}
+	}
+	event := func() func(*Conn) error {
+		return func(c *Conn) error {
+			_, err := c.conn.Write([]byte("event"))
+			if err != nil {
+				return errors.New(fmt.Sprintf("asked dummy server to send event, but resulted in error: %v\n", err))
+			}
+			return err
+		}
+	}
+	waitEvent := func(wantError bool) func(*Conn) error {
+		return func(c *Conn) error {
+			_, err := c.WaitForEvent()
+			if wantError && err == nil {
+				return errors.New(fmt.Sprintf("wait for event resulted in nil error, want some error"))
+			}
+			if !wantError && err != nil {
+				return errors.New(fmt.Sprintf("wait for event resulted in error %v, want nil error", err))
+			}
+			return nil
+		}
+	}
+	checkClosed := func(c *Conn) error {
+		select {
+		case eoe, ok := <-c.eventChan:
+			if ok {
+				return fmt.Errorf("(*Conn).eventChan should be closed, but is not and returns %v", eoe)
+			}
+		case <-time.After(timeout):
+			return fmt.Errorf("(*Conn).eventChan should be closed, but is not and was blocking for %v", timeout)
+		}
+		return nil
+	}
+
+	testCases := []struct {
+		description string
+		actions     []func(*Conn) error
+	}{
+		{"close",
+			[]func(*Conn) error{},
+		},
+		{"double close",
+			[]func(*Conn) error{
+				func(c *Conn) error {
+					c.Close()
+					return nil
+				},
+			},
+		},
+		{"checked requests with reply",
+			[]func(*Conn) error{
+				checkedReply(false),
+				checkedReply(true),
+				checkedReply(false),
+				checkedReply(true),
+			},
+		},
+		{"checked requests no reply",
+			[]func(*Conn) error{
+				checkedNoreply(false),
+				checkedNoreply(true),
+				checkedNoreply(false),
+				checkedNoreply(true),
+			},
+		},
+		{"unchecked requests with reply",
+			[]func(*Conn) error{
+				uncheckedReply(false),
+				uncheckedReply(true),
+				waitEvent(true),
+				uncheckedReply(false),
+				event(),
+				waitEvent(false),
+			},
+		},
+		{"unchecked requests no reply",
+			[]func(*Conn) error{
+				uncheckedNoreply(false),
+				uncheckedNoreply(true),
+				waitEvent(true),
+				uncheckedNoreply(false),
+				event(),
+				waitEvent(false),
+			},
+		},
+		{"close with pending requests",
+			[]func(*Conn) error{
+				func(c *Conn) error {
+					c.conn.(*dNC).ReadLock()
+					defer c.conn.(*dNC).ReadUnlock()
+					c.NewRequest([]byte("reply"), c.NewCookie(false, true))
+					c.Close()
+					return nil
+				},
+				checkClosed,
+			},
+		},
+		{"unexpected conn close",
+			[]func(*Conn) error{
+				func(c *Conn) error {
+					c.conn.Close()
+					if ev, err := c.WaitForEvent(); ev != nil || err != nil {
+						return fmt.Errorf("WaitForEvent() = (%v, %v), want (nil, nil)", ev, err)
+					}
+					return nil
+				},
+				checkClosed,
+			},
+		},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.description, func(t *testing.T) {
+			sclm := leaksMonitor("after server close, before testcase exit")
+			defer sclm.checkTesting(t)
+
+			s := newDummyNetConn("dummyX", newDummyXServerReplier())
+			defer s.Close()
+
+			c, err := postNewConn(&Conn{conn: s})
+			if err != nil {
+				t.Errorf("connect to dummy server error: %v", err)
+				return
+			}
+
+			defer leaksMonitor("after actions end", sclm).checkTesting(t)
+
+			for _, action := range tc.actions {
+				if err := action(c); err != nil {
+					t.Error(err)
+					break
+				}
+			}
+
+			recovered := false
+			func() {
+				defer func() {
+					if err := recover(); err != nil {
+						t.Errorf("(*Conn).Close() panic recover: %v", err)
+						recovered = true
+					}
+				}()
+
+				c.Close()
+			}()
+			if !recovered {
+				if err := checkClosed(c); err != nil {
+					t.Error(err)
+				}
+			}
+
+		})
+	}
+}