if err != nil {
				t.Errorf("obscuretestdata.DecodeToTempFile(%s): %v", path, err)
				return
			}
			defer os.Remove(tf)
			path = tf
		}
		var rc *ReadCloser
		rc, err = OpenReader(path)
		if err == nil {
			defer rc.Close()
			z = &rc.Reader
		}
		var err2 error
		raw, err2 = os.ReadFile(path)
		if err2 != nil {

func TestNegativeRead(t *testing.T) {
	// should panic with a description pointing at the reader, not at itself.
	// (should NOT panic with slice index error, for example.)
	b := NewReader(new(negativeReader))
	defer func() {
		switch err := recover().(type) {
		case nil:
			t.Fatal("read did not panic")
		case error:
			if !strings.Contains(err.Error(), "reader returned negative count from Read") {

	// literal to evaluate the arguments at the right time.
	//    defer func() func() {
	//            _cgo0 := p
	//            return func() {
	//                    _cgoCheckPointer(_cgo0, nil)
	//                    C.f(_cgo0)
	//            }
	//    }()()
	// This works because the defer statement evaluates the first
	// function literal in order to get the function to call.

		}
	}
}

func TestBufferGrowNegative(t *testing.T) {
	defer func() {
		if err := recover(); err == nil {
			t.Fatal("Grow(-1) should have panicked")
		}
	}()
	var b Buffer
	b.Grow(-1)
}

func TestBufferTruncateNegative(t *testing.T) {
	defer func() {
		if err := recover(); err == nil {
			t.Fatal("Truncate(-1) should have panicked")
		}
	}()