Method TestReportError

internal/resolver/dns/dns_resolver_test.go:1317–1365

Test verifies that when the DNS resolver gets an error from the underlying net.Resolver, it reports the error to the channel and backs off and retries.

(t *testing.T)

// Test verifies that when the DNS resolver gets an error from the underlying
// net.Resolver, it reports the error to the channel and backs off and retries.
func (s) TestReportError(t *testing.T) {
	durChan, timeChan := overrideTimeAfterFuncWithChannel(t)
	overrideNetResolver(t, &testNetResolver{})

	const target = "notfoundaddress"
	_, _, errorCh := buildResolverWithTestClientConn(t, target)

	// Should receive first error.
	ctx, ctxCancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer ctxCancel()
	select {
	case <-ctx.Done():
		t.Fatal("Timeout when waiting for an error from the resolver")
	case err := <-errorCh:
		if !strings.Contains(err.Error(), "hostLookup error") {
			t.Fatalf(`ReportError(err=%v) called; want err contains "hostLookupError"`, err)
		}
	}

	// Expect the DNS resolver to backoff and attempt to re-resolve. Every time,
	// the DNS resolver will receive the same error from the net.Resolver and is
	// expected to push it to the channel.
	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
	defer cancel()
	const retries = 10
	var prevDur time.Duration
	for i := 0; i < retries; i++ {
		select {
		case <-ctx.Done():
			t.Fatalf("(Iteration: %d): Timeout when waiting for DNS resolver to backoff", i)
		case dur := <-durChan:
			if dur <= prevDur {
				t.Fatalf("(Iteration: %d): Unexpected decrease in amount of time to backoff", i)
			}
		}

		// Unblock the DNS resolver's backoff by pushing the current time.
		timeChan <- time.Now()

		select {
		case <-ctx.Done():
			t.Fatal("Timeout when waiting for an error from the resolver")
		case err := <-errorCh:
			if !strings.Contains(err.Error(), "hostLookup error") {
				t.Fatalf(`ReportError(err=%v) called; want err contains "hostLookupError"`, err)
			}
		}
	}
}

// Override the default dns.ResolvingTimeout with a test duration.
func overrideResolveTimeoutDuration(t *testing.T, dur time.Duration) {