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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /libgo/go/testing/script
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Diffstat (limited to 'libgo/go/testing/script')
-rw-r--r--libgo/go/testing/script/script.go359
-rw-r--r--libgo/go/testing/script/script_test.go75
2 files changed, 434 insertions, 0 deletions
diff --git a/libgo/go/testing/script/script.go b/libgo/go/testing/script/script.go
new file mode 100644
index 000000000..11f5a7425
--- /dev/null
+++ b/libgo/go/testing/script/script.go
@@ -0,0 +1,359 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// This package aids in the testing of code that uses channels.
+package script
+
+import (
+ "fmt"
+ "os"
+ "rand"
+ "reflect"
+ "strings"
+)
+
+// An Event is an element in a partially ordered set that either sends a value
+// to a channel or expects a value from a channel.
+type Event struct {
+ name string
+ occurred bool
+ predecessors []*Event
+ action action
+}
+
+type action interface {
+ // getSend returns nil if the action is not a send action.
+ getSend() sendAction
+ // getRecv returns nil if the action is not a receive action.
+ getRecv() recvAction
+ // getChannel returns the channel that the action operates on.
+ getChannel() interface{}
+}
+
+type recvAction interface {
+ recvMatch(interface{}) bool
+}
+
+type sendAction interface {
+ send()
+}
+
+// isReady returns true if all the predecessors of an Event have occurred.
+func (e Event) isReady() bool {
+ for _, predecessor := range e.predecessors {
+ if !predecessor.occurred {
+ return false
+ }
+ }
+
+ return true
+}
+
+// A Recv action reads a value from a channel and uses reflect.DeepMatch to
+// compare it with an expected value.
+type Recv struct {
+ Channel interface{}
+ Expected interface{}
+}
+
+func (r Recv) getRecv() recvAction { return r }
+
+func (Recv) getSend() sendAction { return nil }
+
+func (r Recv) getChannel() interface{} { return r.Channel }
+
+func (r Recv) recvMatch(chanEvent interface{}) bool {
+ c, ok := chanEvent.(channelRecv)
+ if !ok || c.channel != r.Channel {
+ return false
+ }
+
+ return reflect.DeepEqual(c.value, r.Expected)
+}
+
+// A RecvMatch action reads a value from a channel and calls a function to
+// determine if the value matches.
+type RecvMatch struct {
+ Channel interface{}
+ Match func(interface{}) bool
+}
+
+func (r RecvMatch) getRecv() recvAction { return r }
+
+func (RecvMatch) getSend() sendAction { return nil }
+
+func (r RecvMatch) getChannel() interface{} { return r.Channel }
+
+func (r RecvMatch) recvMatch(chanEvent interface{}) bool {
+ c, ok := chanEvent.(channelRecv)
+ if !ok || c.channel != r.Channel {
+ return false
+ }
+
+ return r.Match(c.value)
+}
+
+// A Closed action matches if the given channel is closed. The closing is
+// treated as an event, not a state, thus Closed will only match once for a
+// given channel.
+type Closed struct {
+ Channel interface{}
+}
+
+func (r Closed) getRecv() recvAction { return r }
+
+func (Closed) getSend() sendAction { return nil }
+
+func (r Closed) getChannel() interface{} { return r.Channel }
+
+func (r Closed) recvMatch(chanEvent interface{}) bool {
+ c, ok := chanEvent.(channelClosed)
+ if !ok || c.channel != r.Channel {
+ return false
+ }
+
+ return true
+}
+
+// A Send action sends a value to a channel. The value must match the
+// type of the channel exactly unless the channel if of type chan interface{}.
+type Send struct {
+ Channel interface{}
+ Value interface{}
+}
+
+func (Send) getRecv() recvAction { return nil }
+
+func (s Send) getSend() sendAction { return s }
+
+func (s Send) getChannel() interface{} { return s.Channel }
+
+type empty struct {
+ x interface{}
+}
+
+func newEmptyInterface(e empty) reflect.Value {
+ return reflect.NewValue(e).(*reflect.StructValue).Field(0)
+}
+
+func (s Send) send() {
+ // With reflect.ChanValue.Send, we must match the types exactly. So, if
+ // s.Channel is a chan interface{} we convert s.Value to an interface{}
+ // first.
+ c := reflect.NewValue(s.Channel).(*reflect.ChanValue)
+ var v reflect.Value
+ if iface, ok := c.Type().(*reflect.ChanType).Elem().(*reflect.InterfaceType); ok && iface.NumMethod() == 0 {
+ v = newEmptyInterface(empty{s.Value})
+ } else {
+ v = reflect.NewValue(s.Value)
+ }
+ c.Send(v)
+}
+
+// A Close action closes the given channel.
+type Close struct {
+ Channel interface{}
+}
+
+func (Close) getRecv() recvAction { return nil }
+
+func (s Close) getSend() sendAction { return s }
+
+func (s Close) getChannel() interface{} { return s.Channel }
+
+func (s Close) send() { reflect.NewValue(s.Channel).(*reflect.ChanValue).Close() }
+
+// A ReceivedUnexpected error results if no active Events match a value
+// received from a channel.
+type ReceivedUnexpected struct {
+ Value interface{}
+ ready []*Event
+}
+
+func (r ReceivedUnexpected) String() string {
+ names := make([]string, len(r.ready))
+ for i, v := range r.ready {
+ names[i] = v.name
+ }
+ return fmt.Sprintf("received unexpected value on one of the channels: %#v. Runnable events: %s", r.Value, strings.Join(names, ", "))
+}
+
+// A SetupError results if there is a error with the configuration of a set of
+// Events.
+type SetupError string
+
+func (s SetupError) String() string { return string(s) }
+
+func NewEvent(name string, predecessors []*Event, action action) *Event {
+ e := &Event{name, false, predecessors, action}
+ return e
+}
+
+// Given a set of Events, Perform repeatedly iterates over the set and finds the
+// subset of ready Events (that is, all of their predecessors have
+// occurred). From that subset, it pseudo-randomly selects an Event to perform.
+// If the Event is a send event, the send occurs and Perform recalculates the ready
+// set. If the event is a receive event, Perform waits for a value from any of the
+// channels that are contained in any of the events. That value is then matched
+// against the ready events. The first event that matches is considered to
+// have occurred and Perform recalculates the ready set.
+//
+// Perform continues this until all Events have occurred.
+//
+// Note that uncollected goroutines may still be reading from any of the
+// channels read from after Perform returns.
+//
+// For example, consider the problem of testing a function that reads values on
+// one channel and echos them to two output channels. To test this we would
+// create three events: a send event and two receive events. Each of the
+// receive events must list the send event as a predecessor but there is no
+// ordering between the receive events.
+//
+// send := NewEvent("send", nil, Send{c, 1})
+// recv1 := NewEvent("recv 1", []*Event{send}, Recv{c, 1})
+// recv2 := NewEvent("recv 2", []*Event{send}, Recv{c, 1})
+// Perform(0, []*Event{send, recv1, recv2})
+//
+// At first, only the send event would be in the ready set and thus Perform will
+// send a value to the input channel. Now the two receive events are ready and
+// Perform will match each of them against the values read from the output channels.
+//
+// It would be invalid to list one of the receive events as a predecessor of
+// the other. At each receive step, all the receive channels are considered,
+// thus Perform may see a value from a channel that is not in the current ready
+// set and fail.
+func Perform(seed int64, events []*Event) (err os.Error) {
+ r := rand.New(rand.NewSource(seed))
+
+ channels, err := getChannels(events)
+ if err != nil {
+ return
+ }
+ multiplex := make(chan interface{})
+ for _, channel := range channels {
+ go recvValues(multiplex, channel)
+ }
+
+Outer:
+ for {
+ ready, err := readyEvents(events)
+ if err != nil {
+ return err
+ }
+
+ if len(ready) == 0 {
+ // All events occurred.
+ break
+ }
+
+ event := ready[r.Intn(len(ready))]
+ if send := event.action.getSend(); send != nil {
+ send.send()
+ event.occurred = true
+ continue
+ }
+
+ v := <-multiplex
+ for _, event := range ready {
+ if recv := event.action.getRecv(); recv != nil && recv.recvMatch(v) {
+ event.occurred = true
+ continue Outer
+ }
+ }
+
+ return ReceivedUnexpected{v, ready}
+ }
+
+ return nil
+}
+
+// getChannels returns all the channels listed in any receive events.
+func getChannels(events []*Event) ([]interface{}, os.Error) {
+ channels := make([]interface{}, len(events))
+
+ j := 0
+ for _, event := range events {
+ if recv := event.action.getRecv(); recv == nil {
+ continue
+ }
+ c := event.action.getChannel()
+ if _, ok := reflect.NewValue(c).(*reflect.ChanValue); !ok {
+ return nil, SetupError("one of the channel values is not a channel")
+ }
+
+ duplicate := false
+ for _, other := range channels[0:j] {
+ if c == other {
+ duplicate = true
+ break
+ }
+ }
+
+ if !duplicate {
+ channels[j] = c
+ j++
+ }
+ }
+
+ return channels[0:j], nil
+}
+
+// recvValues is a multiplexing helper function. It reads values from the given
+// channel repeatedly, wrapping them up as either a channelRecv or
+// channelClosed structure, and forwards them to the multiplex channel.
+func recvValues(multiplex chan<- interface{}, channel interface{}) {
+ c := reflect.NewValue(channel).(*reflect.ChanValue)
+
+ for {
+ v := c.Recv()
+ if c.Closed() {
+ multiplex <- channelClosed{channel}
+ return
+ }
+
+ multiplex <- channelRecv{channel, v.Interface()}
+ }
+}
+
+type channelClosed struct {
+ channel interface{}
+}
+
+type channelRecv struct {
+ channel interface{}
+ value interface{}
+}
+
+// readyEvents returns the subset of events that are ready.
+func readyEvents(events []*Event) ([]*Event, os.Error) {
+ ready := make([]*Event, len(events))
+
+ j := 0
+ eventsWaiting := false
+ for _, event := range events {
+ if event.occurred {
+ continue
+ }
+
+ eventsWaiting = true
+ if event.isReady() {
+ ready[j] = event
+ j++
+ }
+ }
+
+ if j == 0 && eventsWaiting {
+ names := make([]string, len(events))
+ for _, event := range events {
+ if event.occurred {
+ continue
+ }
+ names[j] = event.name
+ }
+
+ return nil, SetupError("dependency cycle in events. These events are waiting to run but cannot: " + strings.Join(names, ", "))
+ }
+
+ return ready[0:j], nil
+}
diff --git a/libgo/go/testing/script/script_test.go b/libgo/go/testing/script/script_test.go
new file mode 100644
index 000000000..e9ab142c2
--- /dev/null
+++ b/libgo/go/testing/script/script_test.go
@@ -0,0 +1,75 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package script
+
+import (
+ "testing"
+)
+
+func TestNoop(t *testing.T) {
+ err := Perform(0, nil)
+ if err != nil {
+ t.Errorf("Got error: %s", err)
+ }
+}
+
+func TestSimple(t *testing.T) {
+ c := make(chan int)
+ defer close(c)
+
+ a := NewEvent("send", nil, Send{c, 1})
+ b := NewEvent("recv", []*Event{a}, Recv{c, 1})
+
+ err := Perform(0, []*Event{a, b})
+ if err != nil {
+ t.Errorf("Got error: %s", err)
+ }
+}
+
+func TestFail(t *testing.T) {
+ c := make(chan int)
+ defer close(c)
+
+ a := NewEvent("send", nil, Send{c, 2})
+ b := NewEvent("recv", []*Event{a}, Recv{c, 1})
+
+ err := Perform(0, []*Event{a, b})
+ if err == nil {
+ t.Errorf("Failed to get expected error")
+ } else if _, ok := err.(ReceivedUnexpected); !ok {
+ t.Errorf("Error returned was of the wrong type: %s", err)
+ }
+}
+
+func TestClose(t *testing.T) {
+ c := make(chan int)
+
+ a := NewEvent("close", nil, Close{c})
+ b := NewEvent("closed", []*Event{a}, Closed{c})
+
+ err := Perform(0, []*Event{a, b})
+ if err != nil {
+ t.Errorf("Got error: %s", err)
+ }
+}
+
+func matchOne(v interface{}) bool {
+ if i, ok := v.(int); ok && i == 1 {
+ return true
+ }
+ return false
+}
+
+func TestRecvMatch(t *testing.T) {
+ c := make(chan int)
+
+ a := NewEvent("send", nil, Send{c, 1})
+ b := NewEvent("recv", []*Event{a}, RecvMatch{c, matchOne})
+
+ err := Perform(0, []*Event{a, b})
+ if err != nil {
+ t.Errorf("Got error: %s", err)
+ }
+}