Calculate winners ignores ignored choices #247 (#311)

* Calculate winners ignores ignored choices #247

Author: szirbucz

src/main/java/org/rulez/demokracia/pdengine/CanCalculateWinners.java

@@ -0,0 +1,8 @@
+package org.rulez.demokracia.pdengine;
+
+import java.util.List;
+
+public interface CanCalculateWinners {
+
+	List<String> calculateWinners(List<String> ignoredChoices);
+}

src/main/java/org/rulez/demokracia/pdengine/ComputedVote.java

@@ -2,18 +2,27 @@
 
 import java.io.Serializable;
 import java.util.List;
+import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
 
-public class ComputedVote implements ComputedVoteInterface, Serializable {
+import org.rulez.demokracia.pdengine.dataobjects.Pair;
+
+import jersey.repackaged.com.google.common.collect.Sets;
+import jersey.repackaged.com.google.common.collect.Sets.SetView;
+
+public class ComputedVote implements CanCalculateWinners, ComputedVoteInterface, Serializable {
 
 	private static final long serialVersionUID = 1L;
 	private BeatTable beatTable;
 	private final Vote vote;
 	private BeatTable beatPathTable;
 
+	private transient WinnerCalculator winnerCalculator;
+
 	public ComputedVote(final Vote vote) {
 		this.vote = vote;
+		winnerCalculator = new WinnerCalculatorImpl();
 	}
 
 	@Override
@@ -31,11 +40,35 @@ public void computeVote() {
 		beatPathTable.computeTransitiveClosure();
 	}
 
+	@Override
+	public List<String> calculateWinners(final List<String> ignoredChoices) {
+		BeatTable filteredBeatTable = ignoreChoices(ignoredChoices);
+		return winnerCalculator.calculateWinners(filteredBeatTable);
+	}
+
 	public BeatTable getBeatTable() {
 		return beatTable;
 	}
 
 	public BeatTable getBeatPathTable() {
 		return beatPathTable;
 	}
+
+	public void setWinnerCalculator(final WinnerCalculatorImpl winnerCalculator) {
+		this.winnerCalculator = winnerCalculator;
+	}
+
+	private BeatTable ignoreChoices(final List<String> ignoredChoices) {
+		SetView<String> activeChoices = Sets.difference(Sets.newHashSet(beatPathTable.getKeyCollection()),
+				Sets.newHashSet(ignoredChoices));
+		BeatTable filteredBeatTable = new BeatTable(activeChoices);
+		for (String key1 : activeChoices) {
+			for (String key2 : activeChoices) {
+				Pair source = beatTable.getElement(key1, key2);
+				if (Objects.nonNull(source))
+					filteredBeatTable.setElement(key1, key2, source);
+			}
+		}
+		return filteredBeatTable;
+	}
 }

src/main/java/org/rulez/demokracia/pdengine/WinnerCalculator.java

@@ -0,0 +1,8 @@
+package org.rulez.demokracia.pdengine;
+
+import java.util.List;
+
+public interface WinnerCalculator {
+
+	List<String> calculateWinners(final BeatTable beatTable);
+}

src/main/java/org/rulez/demokracia/pdengine/WinnerCalculatorImpl.java

@@ -0,0 +1,12 @@
+package org.rulez.demokracia.pdengine;
+
+import java.util.List;
+
+public class WinnerCalculatorImpl implements WinnerCalculator {
+
+	@Override
+	public List<String> calculateWinners(final BeatTable beatTable) {
+		throw new UnsupportedOperationException();
+	}
+
+}

src/test/java/org/rulez/demokracia/pdengine/CalculateWinnersTest.java

@@ -0,0 +1,66 @@
+package org.rulez.demokracia.pdengine;
+
+import static org.junit.Assert.*;
+import static org.mockito.Mockito.*;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.stubbing.Answer;
+import org.rulez.demokracia.pdengine.annotations.TestedBehaviour;
+import org.rulez.demokracia.pdengine.annotations.TestedFeature;
+import org.rulez.demokracia.pdengine.annotations.TestedOperation;
+import org.rulez.demokracia.pdengine.testhelpers.CreatedDefaultCastVoteWithRankedChoices;
+
+@TestedFeature("Vote")
+@TestedOperation("calculate winners")
+public class CalculateWinnersTest extends CreatedDefaultCastVoteWithRankedChoices {
+
+	private final Answer<?> answerKeyCollection = (invocation) -> {
+		BeatTable beatTable = (BeatTable) invocation.getArguments()[0];
+		return beatTable.getKeyCollection().stream().collect(Collectors.toList());
+	};
+
+	private ComputedVote computedVote;
+	private final ArgumentCaptor<BeatTable> captor = ArgumentCaptor.forClass(BeatTable.class);
+
+	@Override
+	@Before
+	public void setUp() {
+		super.setUp();
+		getTheVote().votesCast = castVote;
+		WinnerCalculatorImpl winnerCalculator = mock(WinnerCalculatorImpl.class);
+		when(winnerCalculator.calculateWinners(captor.capture())).thenAnswer(answerKeyCollection);
+
+		computedVote = new ComputedVote(getTheVote());
+		computedVote.computeVote();
+		computedVote.setWinnerCalculator(winnerCalculator);
+	}
+
+	@TestedBehaviour("only choices not in ignoredChoices are considered")
+	@Test
+	public void calculate_winners_returns_none_of_the_ignored_choices() {
+		List<String> winners = computedVote.calculateWinners(Arrays.asList("A"));
+		assertFalse(winners.contains("A"));
+
+	}
+
+	@TestedBehaviour("only choices not in ignoredChoices are considered")
+	@Test
+	public void calculate_winners_returns_not_ignored_winner() {
+		List<String> winners = computedVote.calculateWinners(Arrays.asList("C"));
+		assertBeatTableContainChoice(winners, "A");
+	}
+
+	private void assertBeatTableContainChoice(final List<String> winners, final String choice) {
+		assertTrue(winners.contains(choice));
+		BeatTable capturedBeatTable = captor.getValue();
+		assertNotNull(capturedBeatTable.getElement(choice, "B"));
+	}
+
+
+}

src/test/java/org/rulez/demokracia/pdengine/UnimplementedTests.java

@@ -16,4 +16,9 @@ public class UnimplementedTests extends ThrowableTester {
 	public void the_getAssurances_method_is_not_implemented_yet() {
 		assertUnimplemented(() -> new CastVote("proxyId", new ArrayList<>()).getAssurances());
 	}
+
+	@Test
+	public void the_calculateWinners_method_is_not_implemented_yet() {
+		assertUnimplemented(() -> new WinnerCalculatorImpl().calculateWinners(null));
+	}
 }