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func WaitFor() the best alternative for assert.Eventually()
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package testhelpers | |
import ( | |
"sync" | |
"time" | |
) | |
// WaitFor calls fn (once in tick) until it passes or timeout expired. | |
// | |
// Attempt is failed if any of following methods called in fn: | |
// - [TestingT].Fail() | |
// - [TestingT].FailNow() | |
// - [TestingT].Error() | |
// - [TestingT].Errorf() | |
// - [TestingT].Fatal() | |
// - [TestingT].Fatalf() | |
// | |
// Otherwise attempt is considered as successful and WaitFor stops. | |
// | |
// WaitFor receives test object as the first argument. | |
// It is passed to fn only on the last attempt. All other attempts use fakeT. | |
// So the test will fail only after timeout expired. | |
// | |
// Note: [TestingT].Log() and other methods will print to stdout only on the last attempt. | |
func WaitFor(t TestingT, timeout time.Duration, tick time.Duration, fn func(t TestingT)) { | |
timer := time.NewTimer(timeout) | |
ticker := time.NewTicker(tick) | |
defer timer.Stop() | |
defer ticker.Stop() | |
for { | |
ft := &fakeT{name: t.Name()} | |
didPanic := false | |
func() { | |
defer func() { | |
if recover() != nil { | |
didPanic = true | |
} | |
}() | |
fn(ft) | |
}() | |
if !ft.Failed() && !didPanic { | |
return | |
} | |
select { | |
case <-timer.C: | |
fn(t) | |
return | |
case <-ticker.C: | |
} | |
} | |
} | |
type TestingT interface { | |
Error(args ...interface{}) | |
Errorf(format string, args ...interface{}) | |
Fail() | |
FailNow() | |
Failed() bool | |
Fatal(args ...interface{}) | |
Fatalf(format string, args ...interface{}) | |
Log(args ...interface{}) | |
Logf(format string, args ...interface{}) | |
Name() string | |
Helper() | |
} | |
type fakeT struct { | |
sync.Mutex | |
failed bool | |
name string | |
} | |
func (t *fakeT) fail() { | |
t.Lock() | |
defer t.Unlock() | |
t.failed = true | |
} | |
func (t *fakeT) panic() { | |
t.fail() | |
panic("panic") | |
} | |
func (t *fakeT) Name() string { | |
t.Lock() | |
defer t.Unlock() | |
return t.name | |
} | |
func (t *fakeT) Failed() bool { | |
t.Lock() | |
defer t.Unlock() | |
return t.failed | |
} | |
func (t *fakeT) Error(args ...interface{}) { t.fail() } | |
func (t *fakeT) Errorf(format string, args ...interface{}) { t.fail() } | |
func (t *fakeT) Fail() { t.fail() } | |
func (t *fakeT) FailNow() { t.panic() } | |
func (t *fakeT) Fatal(args ...interface{}) { t.panic() } | |
func (t *fakeT) Fatalf(format string, args ...interface{}) { t.panic() } | |
func (t *fakeT) Log(args ...interface{}) {} | |
func (t *fakeT) Logf(format string, args ...interface{}) {} | |
func (t *fakeT) Helper() {} |
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package example | |
import ( | |
"testing" | |
"time" | |
"x/testhelpers" | |
"github.com/stretchr/testify/assert" | |
) | |
func TestPassing(t *testing.T) { | |
ch := make(chan struct{}) | |
go func() { | |
time.Sleep(5 * time.Second) | |
ch <- struct{}{} | |
}() | |
testhelpers.WaitFor(t, 10*time.Second, 1*time.Second, func(t testhelpers.TestingT) { | |
select { | |
case <-ch: | |
default: | |
assert.Fail(t, "channel is empty") | |
} | |
}) // PASS - output is empty | |
} | |
func TestFailing(t *testing.T) { | |
var ch chan struct{} | |
testhelpers.WaitFor(t, 10*time.Second, 1*time.Second, func(t testhelpers.TestingT) { | |
select { | |
case <-ch: | |
default: | |
assert.Fail(t, "channel is empty") | |
} | |
}) // FAIL | |
// Output: | |
// TestFailing: x_example_test.go:31: | |
// Error Trace: x_example_test.go:31 | |
// wait_for.go:47 | |
// x_example_test.go:27 | |
// Error: channel is empty | |
// Test: TestFailing | |
} |
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