io.WriteString(f, data)

	f.Seek(0, 0)
	b := make([]byte, 5)

	n, err := f.ReadAt(b, -10)

	const wantsub = "negative offset"
	if !strings.Contains(fmt.Sprint(err), wantsub) || n != 0 {
		t.Errorf("ReadAt(-10) = %v, %v; want 0, ...%q...", n, err, wantsub)
	}
}

func TestWriteAt(t *testing.T) {
	t.Parallel()

	f := newFile("TestWriteAt", t)
	defer Remove(f.Name())

	res, err := cst.c.Get(cst.ts.URL)
	if res != nil {
		defer res.Body.Close()
	}
	got := fmt.Sprint(err)
	wantSub := "too many 1xx informational responses"
	if !strings.Contains(got, wantSub) {
		t.Errorf("Get error = %v; want substring %q", err, wantSub)
	}
}

// Issue 26161: the HTTP client must treat 101 responses
// as the final response.

			// Move just before the backoff end time
			fakeClock.Sleep(delay - 1*time.Nanosecond)
			if !manager.failedPodsBackoff.IsInBackOffSinceUpdate(backoffKey, fakeClock.Now()) {
				t.Errorf("Backoff delay didn't last the whole waitout period.")
			}

			// Move to the backoff end time
			fakeClock.Sleep(1 * time.Nanosecond)
			if manager.failedPodsBackoff.IsInBackOffSinceUpdate(backoffKey, fakeClock.Now()) {

func TestRedirectContentTypeAndBody(t *testing.T) {
	type ctHeader struct {
		Values []string
	}

	var tests = []struct {
		method   string
		ct       *ctHeader // Optional Content-Type header to set.
		wantCT   string
		wantBody string
	}{
		{MethodGet, nil, "text/html; charset=utf-8", "<a href=\"/foo\">Found</a>.\n\n"},
		{MethodHead, nil, "text/html; charset=utf-8", ""},
		{MethodPost, nil, "", ""},