Livt.ML

tests/model/LinearRegressionTest.lvt

namespace Livt.ML.Tests.Model

using Livt.ML.Model

/**
 * Exercises LinearRegression with a shared fixture instance. Each scenario establishes the
 * inputs and state it needs.
 */
@Test
component LinearRegressionTest
{
	// Shared fixture instances, signals, and observation state.
	model: LinearRegression

	/**
	 * Creates the shared fixture instances (LinearRegression). Tests initialize the state
	 * required by their scenario.
	 */
	new()
	{
		model = new LinearRegression()
	}

	/**
	 * Writes six calibration pairs into the supplied arrays; remaining entries are outside the
	 * fitted sample count.
	 */
	fn LoadCalibrationData(x: int[32], y: int[32])
	{
		x[0] = 180
		x[1] = 200
		x[2] = 220
		x[3] = 240
		x[4] = 260
		x[5] = 280

		y[0] = 170
		y[1] = 190
		y[2] = 210
		y[3] = 230
		y[4] = 250
		y[5] = 270
	}

	/**
	 * Checks that Fit s linear model.
	 */
	@Test
	fn FitsLinearModel()
	{
		var x: int[32]
		var y: int[32]
		this.LoadCalibrationData(x, y)

		model.Fit(x, y, 6)

		var aFixed = model.GetAFixed()
		var b = model.GetB()

		assert aFixed > 900
		assert aFixed < 1100
		assert b > -20
		assert b < 0
	}

	/**
	 * Checks that Predict s within training range.
	 */
	@Test
	fn PredictsWithinTrainingRange()
	{
		var x: int[32]
		var y: int[32]
		this.LoadCalibrationData(x, y)

		model.Fit(x, y, 6)

		var predicted = model.Predict(215)

		assert predicted > 200
		assert predicted < 210
	}

	/**
	 * Checks that Predict s training data with small error.
	 */
	@Test
	fn PredictsTrainingDataWithSmallError()
	{
		var x: int[32]
		var y: int[32]
		this.LoadCalibrationData(x, y)

		model.Fit(x, y, 6)

		for (var i = 0; i < 6; i++) {
			var predicted = model.Predict(x[i])
			var error = predicted - y[i]

			if (error < 0) {
				error = -error
			}

			assert error <= 5
		}
	}

	/**
	 * Checks that the component rejects insufficient data.
	 */
	@Test
	fn RejectsInsufficientData()
	{
		var x: int[32]
		var y: int[32]

		x[0] = 100
		y[0] = 90

		model.Fit(x, y, 1)

		assert model.GetAFixed() == 0
		assert model.GetB() == 0
	}

	/**
	 * Checks that the component rejects degenerate data.
	 */
	@Test
	fn RejectsDegenerateData()
	{
		var x: int[32]
		var y: int[32]

		x[0] = 100
		x[1] = 100
		x[2] = 100

		y[0] = 90
		y[1] = 91
		y[2] = 92

		model.Fit(x, y, 3)

		assert model.GetAFixed() == 0
		assert model.GetB() == 0
	}
}