builder = new DefaultMessageBuilder();
        format.formatRate(builder, 1000000000.0); // 1 GB/s
        assertEquals("1.0 GB/s", builder.build());
    }

    @Test
    void testFormatRateEdgeCases() {
        FileSizeFormat format = new FileSizeFormat();

        // Test zero rate
        MessageBuilder builder = new DefaultMessageBuilder();
        format.formatRate(builder, 0.0);