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package message_test
import (
"bytes"
"errors"
"reflect"
"strconv"
"syscall"
"testing"
"hakurei.app/container/stub"
"hakurei.app/message"
)
func TestSuspendable(t *testing.T) {
// copied from output.go
const suspendBufMax = 1 << 24
t.Parallel()
const (
// equivalent to len(want.pt)
nSpecialPtEquiv = -iota - 1
// equivalent to len(want.w)
nSpecialWEquiv
// suspends writer before executing test case, implies nSpecialWEquiv
nSpecialSuspend
// offset: resume writer and measure against dump instead, implies nSpecialPtEquiv
nSpecialDump
)
// shares the same writer
steps := []struct {
name string
w, pt []byte
err error
wantErr error
n int
}{
{"simple", []byte{0xde, 0xad, 0xbe, 0xef}, []byte{0xde, 0xad, 0xbe, 0xef},
nil, nil, nSpecialPtEquiv},
{"error", []byte{0xb, 0xad}, []byte{0xb, 0xad},
stub.UniqueError(0), stub.UniqueError(0), nSpecialPtEquiv},
{"suspend short", []byte{0}, nil,
nil, nil, nSpecialSuspend},
{"sw short 0", []byte{0xca, 0xfe, 0xba, 0xbe}, nil,
nil, nil, nSpecialWEquiv},
{"sw short 1", []byte{0xff}, nil,
nil, nil, nSpecialWEquiv},
{"resume short", nil, []byte{0, 0xca, 0xfe, 0xba, 0xbe, 0xff}, nil, nil,
nSpecialDump},
{"long pt", bytes.Repeat([]byte{0xff}, suspendBufMax+1), bytes.Repeat([]byte{0xff}, suspendBufMax+1),
nil, nil, nSpecialPtEquiv},
{"suspend fill", bytes.Repeat([]byte{0xfe}, suspendBufMax), nil,
nil, nil, nSpecialSuspend},
{"drop", []byte{0}, nil,
nil, syscall.ENOMEM, 0},
{"drop error", []byte{0}, nil,
stub.UniqueError(1), syscall.ENOMEM, 0},
{"resume fill", nil, bytes.Repeat([]byte{0xfe}, suspendBufMax),
nil, nil, nSpecialDump - 2},
{"suspend fill partial", bytes.Repeat([]byte{0xfd}, suspendBufMax-0xf), nil,
nil, nil, nSpecialSuspend},
{"partial write", bytes.Repeat([]byte{0xad}, 0x1f), nil,
nil, syscall.ENOMEM, 0xf},
{"full drop", []byte{0}, nil,
nil, syscall.ENOMEM, 0},
{"resume fill partial", nil, append(bytes.Repeat([]byte{0xfd}, suspendBufMax-0xf), bytes.Repeat([]byte{0xad}, 0xf)...),
nil, nil, nSpecialDump - 0x10 - 1},
}
var dw expectWriter
w := message.Suspendable{Downstream: &dw}
for _, step := range steps {
// these share the same writer, so cannot be subtests
t.Logf("writing step %q", step.name)
dw.expect, dw.err = step.pt, step.err
var (
gotN int
gotErr error
)
wantN := step.n
switch wantN {
case nSpecialPtEquiv:
wantN = len(step.pt)
gotN, gotErr = w.Write(step.w)
case nSpecialWEquiv:
wantN = len(step.w)
gotN, gotErr = w.Write(step.w)
case nSpecialSuspend:
s := w.IsSuspended()
if ok := w.Suspend(); s && ok {
t.Fatal("Suspend: unexpected success")
}
wantN = len(step.w)
gotN, gotErr = w.Write(step.w)
default:
if wantN <= nSpecialDump {
if !w.IsSuspended() {
t.Fatal("IsSuspended unexpected false")
}
resumed, dropped, n, err := w.Resume()
if !resumed {
t.Fatal("Resume: resumed = false")
}
if wantDropped := nSpecialDump - wantN; int(dropped) != wantDropped {
t.Errorf("Resume: dropped = %d, want %d", dropped, wantDropped)
}
wantN = len(step.pt)
gotN, gotErr = int(n), err
} else {
gotN, gotErr = w.Write(step.w)
}
}
if gotN != wantN {
t.Errorf("Write: n = %d, want %d", gotN, wantN)
}
if !reflect.DeepEqual(gotErr, step.wantErr) {
t.Errorf("Write: %v", gotErr)
}
if dw.expect != nil {
t.Errorf("expect: %q", string(dw.expect))
}
}
}
// expectWriter compares Write calls to expect.
type expectWriter struct {
expect []byte
err error
// optional consecutive write
next []byte
// optional, calls Error on failure if not nil
t *testing.T
}
func (w *expectWriter) Write(p []byte) (n int, err error) {
defer func() { w.expect = w.next; w.next = nil }()
n, err = len(p), w.err
if w.expect == nil {
n, err = 0, errors.New("unexpected call to Write: "+strconv.Quote(string(p)))
if w.t != nil {
w.t.Error(err.Error())
}
return
}
if string(p) != string(w.expect) {
n, err = 0, errors.New("p = "+strconv.Quote(string(p))+", want "+strconv.Quote(string(w.expect)))
if w.t != nil {
w.t.Error(err.Error())
}
return
}
return
}
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