Livt.Collections

tests/fifo/AsyncFifoTest.lvt

namespace Livt.Collections.Tests

using Livt.Collections

/**
 * Checks two-context wiring, fill/drain and reuse through the Livt test runner.
 */
@Test
@Context(ClockFrequency=25MHz)
component AsyncFifoTest
{
	// Independent read clock borrowed by the FIFO and monitor.
	@Context(ClockFrequency=50MHz)
	readContext: IContext

	// Owned subject and read-domain scoreboard.
	fifo: AsyncFifo<byte, 4>
	monitor: AsyncFifoReadMonitor

	// Test stimuli held stable across both domains.
	clearBoth: bool
	push: bool
	pop: bool

	/**
	 * Wires the subject and observer to distinct write/read contexts.
	 */
	new()
	{
		this.clearBoth = true
		this.fifo = new AsyncFifo<byte, 4>(this.context, readContext,
			clearBoth, clearBoth, push, 0xA5, pop)
		this.monitor = new AsyncFifoReadMonitor(readContext, clearBoth, fifo.popValid, fifo.popData)
	}

	/**
	 * Checks fill, drain and reuse after coordinated clear across two clocks.
	 */
	@Test
	fn FillDrainAndReuseAcrossContexts()
	{
		this.push = false
		this.pop = false
		this.clearBoth = true
		Simulation.Wait(20)
		assert fifo.writeCleared
		assert fifo.readCleared
		this.clearBoth = false
		Simulation.Wait(20)
		this.push = true
		Simulation.Wait(40)
		assert fifo.full
		this.push = false
		Simulation.Wait(20)
		this.pop = true
		Simulation.Wait(60)
		this.pop = false
		Simulation.Wait(20)
		assert fifo.empty
		var first = sync this.monitor.GetCount()
		assert first == 4
		var firstBadData = sync this.monitor.HasBadData()
		assert !firstBadData

		this.clearBoth = true
		Simulation.Wait(20)
		this.clearBoth = false
		Simulation.Wait(20)
		this.push = true
		Simulation.Wait(40)
		this.push = false
		Simulation.Wait(20)
		this.pop = true
		Simulation.Wait(60)
		this.pop = false
		Simulation.Wait(20)
		var second = sync this.monitor.GetCount()
		assert second == 4
		var bad = sync this.monitor.HasBadData()
		assert !bad
	}
}