Livt.IO

tests/uart/BufferedUartApiTest.lvt

namespace Livt.IO.Tests

using Livt.IO

/**
 * Exercises BufferedUartApi with a shared fixture instance. Each scenario establishes the
 * inputs and state it needs.
 */
@Test
@Context(ClockFrequency = 100MHz)
component BufferedUartApiTest
{
	// Independent 100 MHz/1 Mbaud timing keeps behavioral regressions short.
	const TICKS_PER_BIT: int = 100

	// Shared fixture instances, signals, and observation state.
	uart: BufferedUart<64, 64, UartDataBits.Eight, UartParity.None, UartStopBits.One, 1MHz>

	// Shared fixture instances, signals, and observation state.
	loopback_line: logic = 0b1

	/**
	 * Creates the shared fixture instances (BufferedUart). Tests initialize the state required
	 * by their scenario.
	 */
	new()
	{
		this.uart = new BufferedUart<64, 64, UartDataBits.Eight, UartParity.None, UartStopBits.One, 1MHz>(this.loopback_line, this.loopback_line)
	}

	/**
	 * Checks that Send queues whole message.
	 */
	@Test
	fn TestSendQueuesWholeMessage()
	{
		var message = "Hi".Encode()
		var sent = this.uart.Send(message)
		assert sent == 2

		Simulation.Wait(TICKS_PER_BIT * 25)

		assert this.uart.GetReceiveCount() > 0
		var receivedByte1: byte
		assert this.uart.TryReceive(receivedByte1) == true
		assert receivedByte1 == 0x48
		var receivedByte2: byte
		assert this.uart.TryReceive(receivedByte2) == true
		assert receivedByte2 == 0x69
		assert this.uart.GetReceiveCount() == 0
	}

	/**
	 * Sending an empty prefix succeeds with zero accepted bytes.
	 */
	@Test
	fn TestSendEmptyMessage()
	{
		var message = "".Encode()
		assert this.uart.Send(message) == 0
		assert this.uart.GetTransmitSpace() == 64
	}

	/**
	 * Checks the forwards buffered api case.
	 */
	@Test
	fn TestForwardsBufferedApi()
	{
		assert this.uart.GetReceiveCount() == 0
		assert this.uart.GetTransmitSpace() == 64
		assert this.uart.IsTransmitting() == false

		assert this.uart.TryTransmit(0x33) == true
		assert this.uart.TryTransmit(0x34) == true
		assert this.uart.GetTransmitSpace() < 64

		this.uart.ClearTransmitBuffer()
		assert this.uart.GetTransmitSpace() == 64

		this.uart.ClearReceiveBuffer()
		assert this.uart.GetReceiveCount() == 0
	}
}