pass testing.T explicitly to the anonymous func

[hidetatz]

What does this pull request do?

Passes testing.T explicitly to the anonymous function run as a goroutine. By this change, go vet succeeds.
Fixes #412

Where should the reviewer start?

Read #412 to understand the problem and make sure testing.T is correctly used.

How should this be manually tested?

Run go vet locally.

[shogo82148]

Thanks for your contribution, but it just deceives go vet and is not an essential solution.
We need to wait for all the goroutines to finish before calling (*T).Fatalf.

[nathany]

I did see some example solutions when I searched the Internet for the vet error... there's a better way to do it, I'm certain.

Little point in running go vet if we're going to trick it.

[hidetatz]

Does it make sense to use errgroup? I'm writing patch like this:

diff --git a/inotify_poller_test.go b/inotify_poller_test.go
index 0570057..80a2bb5 100644
--- a/inotify_poller_test.go
+++ b/inotify_poller_test.go
@@ -11,6 +11,7 @@ import (
 	"testing"
 	"time"
 
+	"golang.org/x/sync/errgroup"
 	"golang.org/x/sys/unix"
 )
 
@@ -174,19 +175,23 @@ func TestPollerConcurrent(t *testing.T) {
 	oks := make(chan bool)
 	live := make(chan bool)
 	defer close(live)
-	go func(tb testing.TB) {
+	eg := errgroup.Group{}
+	eg.Go(func() error {
 		defer close(oks)
 		for {
 			ok, err := poller.wait()
 			if err != nil {
-				tb.Fatalf("poller failed: %v", err)
+				return err
 			}
 			oks <- ok
 			if !<-live {
-				return
+				return nil
 			}
 		}
-	}(t)
+	})
+	if err := eg.Wait(); err != nil {
+		t.Fatalf("poller failed: %v", err)
+	}
 
 	// Try a write
 	select {

[nathany]

That looks like a very nice solution

It does mean adding another dependency, but only for tests. 🤔

I'm not sure what other people think, but if you're willing to open a PR for that, it'd be a good start. There are multiple platforms where the vet error occurs.

[hidetatz]

Another way is using sync.WaitGroup instead of errgroup if introducing another dependency is unacceptable, but using errgroup is clearer way for me.
OK, I'll open another PR.

There are multiple platforms where the vet error occurs.

Got it, I think something like GOOS=windows GOARCH=amd64 go vet ./... will work.

[nathany]

👍🏼 I'll let you decide -- if you can make sync.WaitGroup work nicely (maybe adding a helper function or what not), that may be preferred.

Kind've need a way to trigger the error case to make sure it all works, because normally Fatalf shouldn't be called. :-)

[shogo82148]

yeah, errgroup is a good choice.
however I think sync.WaitGroup is enough to resolve it.

Here is my patch: #416