chromedp/context_test.go
Daniel Martí 939d377090 avoid hanging when Chrome is closed separately
It's Run that actually starts a Browser, not NewContext. If the browser
is closed or crashes, the browser handler will fail to read from the
websocket, and its goroutines will stop.

However, the target handler's goroutines may not stop. The browser
handler uses a separate cancel function to stop itself when encountering
a websocket error, so that doesn't propagate to the original context
children, like the target handler.

To fix this, make it so that NewContext can keep the cancel function
around, for Run to use it in this scenario. And add a test case that
tests this very edge case, which used to time out before the fix.

Fixes #289.
2019-04-07 19:28:41 +02:00

101 lines
2.2 KiB
Go

package chromedp
import (
"context"
"fmt"
"net/http"
"net/http/httptest"
"os"
"runtime"
"testing"
"time"
)
func TestTargets(t *testing.T) {
t.Parallel()
// Start one browser with one tab.
ctx1, cancel1 := NewContext(context.Background())
defer cancel1()
if err := Run(ctx1); err != nil {
t.Fatal(err)
}
wantTargets := func(ctx context.Context, want int) {
t.Helper()
infos, err := Targets(ctx)
if err != nil {
t.Fatal(err)
}
if got := len(infos); want != got {
t.Fatalf("want %d targets, got %d", want, got)
}
}
wantTargets(ctx1, 1)
// Start a second tab on the same browser.
ctx2, cancel2 := NewContext(ctx1)
defer cancel2()
if err := Run(ctx2); err != nil {
t.Fatal(err)
}
wantTargets(ctx2, 2)
// The first context should also see both targets.
wantTargets(ctx1, 2)
// Cancelling the second context should close the second tab alone.
cancel2()
wantTargets(ctx1, 1)
// We used to have a bug where Run would reset the first context as if
// it weren't the first, breaking its cancellation.
if err := Run(ctx1); err != nil {
t.Fatal(err)
}
}
func TestBrowserQuit(t *testing.T) {
t.Parallel()
if runtime.GOOS == "windows" {
t.Skip("os.Interrupt isn't supported on Windows")
}
// Simulate a scenario where we navigate to a page that's slow to
// respond, and the browser is closed before we can finish the
// navigation.
serve := make(chan bool, 1)
close := make(chan bool, 1)
s := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
close <- true
<-serve
fmt.Fprintf(w, "response")
}))
defer s.Close()
ctx, cancel := NewContext(context.Background())
defer cancel()
if err := Run(ctx); err != nil {
t.Fatal(err)
}
go func() {
<-close
b := FromContext(ctx).Browser
if err := b.process.Signal(os.Interrupt); err != nil {
t.Error(err)
}
serve <- true
}()
// Run should error with something other than "deadline exceeded" in
// much less than 5s.
ctx2, _ := context.WithTimeout(ctx, 5*time.Second)
switch err := Run(ctx2, Navigate(s.URL)); err {
case nil:
t.Fatal("did not expect a nil error")
case context.DeadlineExceeded:
t.Fatalf("did not expect a standard context error: %v", err)
}
}