Merge pull request #82 from pierredavidbelanger/schrimpf-acceptance-test

SchrimpfAcceptance unit tests

jsprit-core/src/test/java/jsprit/core/algorithm/acceptor/SchrimpfAcceptanceTest.java

@@ -0,0 +1,73 @@
+package jsprit.core.algorithm.acceptor;
+
+import jsprit.core.problem.solution.VehicleRoutingProblemSolution;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+public class SchrimpfAcceptanceTest {
+
+	protected SchrimpfAcceptance schrimpfAcceptance;
+	protected Collection<VehicleRoutingProblemSolution> memory;
+
+	protected static VehicleRoutingProblemSolution createSolutionWithCost(double cost) {
+		return when(mock(VehicleRoutingProblemSolution.class).getCost()).thenReturn(cost).getMock();
+	}
+
+	@Before
+	public void setup() {
+		schrimpfAcceptance = new SchrimpfAcceptance(1, 0.3, 100);
+		// we skip the warmup, but still want to test that the initialThreshold is set
+		schrimpfAcceptance.setInitialThreshold(0.0);
+		// create empty memory with an initial capacity of 1
+		memory = new ArrayList<VehicleRoutingProblemSolution>(1);
+		// insert the initial (worst) solution, will be accepted anyway since its the first in the memory
+		assertTrue("Solution (initial cost = 2.0) should be accepted since the memory is empty", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(2.0)));
+	}
+
+	@Test
+	public void respectsTheZeroThreshold_usingWorstCostSolution() {
+		assertFalse("Worst cost solution (2.1 > 2.0) should not be accepted", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(2.1)));
+	}
+
+	@Test
+	public void respectsTheZeroThreshold_usingBetterCostSolution() {
+		assertTrue("Better cost solution (1.9 < 2.0) should be accepted", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(1.9)));
+	}
+
+	@Test
+	public void respectsTheZeroThreshold_usingSameCostSolution() {
+		assertFalse("Same cost solution (2.0 == 2.0) should not be accepted", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(2.0)));
+	}
+
+	@Test
+	public void respectsTheNonZeroThreshold_usingWorstCostSolution() {
+		schrimpfAcceptance.setInitialThreshold(0.5);
+		assertFalse("Worst cost solution (2.1 > 2.0) should not be accepted", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(2.1)));
+	}
+
+	@Test
+	public void respectsTheNonZeroThreshold_usingBetterCostSolution() {
+		schrimpfAcceptance.setInitialThreshold(0.5);
+		assertTrue("Better cost solution (1.0 < 2.0) should be accepted since the better cost bust the threshold", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(1.0)));
+	}
+
+	@Test
+	public void respectsTheNonZeroThreshold_usingBetterButBelowTheThresholdCostSolution() {
+		schrimpfAcceptance.setInitialThreshold(0.5);
+		assertFalse("Better cost solution (1.9 < 2.0) should not be accepted since the better cost is still below the threshold", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(1.9)));
+	}
+
+	@Test
+	public void respectsTheNonZeroThreshold_usingSameCostSolution() {
+		schrimpfAcceptance.setInitialThreshold(0.5);
+		assertFalse("Same cost solution (2.0 == 2.0) should not be accepted", schrimpfAcceptance.acceptSolution(memory, createSolutionWithCost(2.0)));
+	}
+}