Livt.Usb

tests/PacketBufferTest.lvt

namespace Livt.Usb.Tests

using Livt.IO
using Livt.Usb.Packets

/**
 * Compares the default block-style and resettable logic-array backends at 64 bytes.
 * Each test clears metadata explicitly; no test depends on unwritten payload values.
 */
@Test
component PacketBufferTest
{
	// Independent implementations receiving the same serialized operations.
	block: PacketBuffer
	array: PacketBuffer<64, MemoryStyle.Block, ArrayRam<byte, 64>>

	/**
	 * Owns both buffers in the inherited test context.
	 */
	new()
	{
		block = new PacketBuffer()
		array = new PacketBuffer<64, MemoryStyle.Block, ArrayRam<byte, 64>>()
	}

	/**
	 * Verifies every byte, bounds, immutable publication and shorter reuse on both stores.
	 */
	@Test
	fn PreservesPayloadAndPublicationAcrossBackends()
	{
		block.Clear()
		array.Clear()
		var blockByte: byte = 0xFF
		var arrayByte: byte = 0xFF
		assert !block.TryRead(0, blockByte)
		assert !array.TryRead(0, arrayByte)
		assert blockByte == 0
		assert arrayByte == 0

		for (var i = 0; i < 64; i++) {
			var expected = ((i * 37 + 128) % 256) as byte
			assert block.TryAppend(expected)
			assert array.TryAppend(expected)
		}

		assert block.GetLength() == 64
		assert array.GetLength() == 64
		assert !block.TryAppend(0xEE)
		assert !array.TryAppend(0xEE)
		assert block.TryPublish()
		assert array.TryPublish()
		assert !block.TryPublish()
		assert !array.TryPublish()
		assert !block.TryAppend(0xEE)
		assert !array.TryAppend(0xEE)

		for (var i = 63; i >= 0; i--) {
			var expected = ((i * 37 + 128) % 256) as byte
			assert block.TryRead(i, blockByte)
			assert array.TryRead(i, arrayByte)
			assert blockByte == expected
			assert arrayByte == expected
		}

		assert !block.TryRead(-1, blockByte)
		assert !array.TryRead(-1, arrayByte)
		assert !block.TryRead(64, blockByte)
		assert !array.TryRead(64, arrayByte)
		assert blockByte == 0
		assert arrayByte == 0
		block.Clear()
		array.Clear()
		assert !block.IsReady()
		assert !array.IsReady()
		assert block.TryAppend(0x42)
		assert array.TryAppend(0x42)
		assert block.TryPublish()
		assert array.TryPublish()
		assert !block.TryAppend(0xEE)
		assert !array.TryAppend(0xEE)
		assert block.GetLength() == 1
		assert array.GetLength() == 1
		assert block.TryRead(0, blockByte)
		assert array.TryRead(0, arrayByte)
		assert blockByte == 0x42
		assert arrayByte == 0x42
		assert !block.TryRead(1, blockByte)
		assert !array.TryRead(1, arrayByte)
		assert blockByte == 0
		assert arrayByte == 0
	}

	/**
	 * Empty publication is distinguishable from an unpublished buffer on both stores.
	 */
	@Test
	fn PublishesZeroLengthPayloadWithoutReadingStorage()
	{
		block.Clear()
		array.Clear()
		assert block.TryPublish()
		assert array.TryPublish()
		assert block.IsReady()
		assert array.IsReady()
		assert block.GetLength() == 0
		assert array.GetLength() == 0
		var value: byte = 0xFF
		assert !block.TryRead(0, value)
		assert value == 0
		assert !array.TryRead(0, value)
		assert value == 0
	}

	/**
	 * Partially staged data stays private and can be discarded before publication.
	 */
	@Test
	fn DiscardsIncompletePayload()
	{
		block.Clear()
		array.Clear()
		assert block.TryAppend(0xA5)
		assert array.TryAppend(0xA5)
		var value: byte = 0xFF
		assert !block.TryRead(0, value)
		assert !array.TryRead(0, value)
		block.Clear()
		array.Clear()
		assert block.GetLength() == 0
		assert array.GetLength() == 0
		assert block.TryPublish()
		assert array.TryPublish()
		assert !block.TryRead(0, value)
		assert !array.TryRead(0, value)
	}
}