Move feedback calculations from Service to Model class

src/main/java/de/thm/arsnova/model/Feedback.java

@@ -27,6 +27,8 @@ import java.util.List;
  * The feedback values of a single session.
  */
 public class Feedback {
+	private static final double Z_THRESHOLD = 0.1;
+
 	public static final int MIN_FEEDBACK_TYPE = 0;
 	public static final int MAX_FEEDBACK_TYPE = 3;
 
@@ -50,6 +52,23 @@ public class Feedback {
 		return values;
 	}
 
+	public double getAverage() {
+		final double count = this.getCount();
+		final double sum = values.get(FEEDBACK_OK) + values.get(FEEDBACK_SLOWER) * 2
+				+ values.get(FEEDBACK_AWAY) * 3;
+
+		if (Math.abs(count) < Z_THRESHOLD) {
+			return 0;
+		}
+
+		return sum / count;
+	}
+
+	public int getCount() {
+		return values.get(FEEDBACK_FASTER) + values.get(FEEDBACK_OK)
+				+ values.get(FEEDBACK_SLOWER) + values.get(FEEDBACK_AWAY);
+	}
+
 	@Override
 	public boolean equals(final Object obj) {
 		if (obj == null) {

src/main/java/de/thm/arsnova/service/FeedbackServiceImpl.java

@@ -42,7 +42,6 @@ import java.util.Set;
 public class FeedbackServiceImpl implements FeedbackService, ApplicationEventPublisherAware {
 
 	private static final int DEFAULT_SCHEDULER_DELAY = 5000;
-	private static final double Z_THRESHOLD = 0.1;
 
 	/**
 	 * minutes, after which the feedback is deleted
@@ -125,28 +124,17 @@ public class FeedbackServiceImpl implements FeedbackService, ApplicationEventPub
 	@Override
 	public int countFeedbackByRoomId(final String roomId) {
 		final Feedback feedback = this.getByRoomId(roomId);
-		final List<Integer> values = feedback.getValues();
-		return values.get(Feedback.FEEDBACK_FASTER) + values.get(Feedback.FEEDBACK_OK)
-				+ values.get(Feedback.FEEDBACK_SLOWER) + values.get(Feedback.FEEDBACK_AWAY);
+		return feedback.getCount();
 	}
 
 	@Override
 	public double calculateAverageFeedback(final String roomId) {
-		final Room room = roomService.get(roomId);
-		if (room == null) {
-			throw new NotFoundException();
-		}
-		final Feedback feedback = feedbackStorage.getByRoom(room);
-		final List<Integer> values = feedback.getValues();
-		final double count = values.get(Feedback.FEEDBACK_FASTER) + values.get(Feedback.FEEDBACK_OK)
-				+ values.get(Feedback.FEEDBACK_SLOWER) + values.get(Feedback.FEEDBACK_AWAY);
-		final double sum = values.get(Feedback.FEEDBACK_OK) + values.get(Feedback.FEEDBACK_SLOWER) * 2
-				+ values.get(Feedback.FEEDBACK_AWAY) * 3;
-
-		if (Math.abs(count) < Z_THRESHOLD) {
+		final Feedback feedback = this.getByRoomId(roomId);
+		if (feedback.getCount() == 0) {
 			throw new NoContentException();
 		}
-		return sum / count;
+
+		return feedback.getAverage();
 	}
 
 	@Override

src/test/java/de/thm/arsnova/model/FeedbackTest.java

@@ -19,8 +19,7 @@ package de.thm.arsnova.model;
 
 import org.junit.Test;
 
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 
 public class FeedbackTest {
 
@@ -64,4 +63,35 @@ public class FeedbackTest {
 		assertFalse(f1.equals(f2));
 		assertFalse(f2.equals(f1));
 	}
+
+	@Test
+	public void shouldCalculateAverageValue() {
+		Feedback f = new Feedback(1, 0, 0, 1);
+
+		double expected = 1.5;
+		double actual = f.getAverage();
+
+		assertEquals(expected, actual, 0.01);
+	}
+
+	@Test
+	public void averageCalculationShouldAvoidDivisionByZero() {
+		Feedback f = new Feedback(0, 0, 0, 0);
+
+		double expected = 0;
+		double actual = f.getAverage();
+
+		assertEquals(expected, actual, 0.01);
+	}
+
+	@Test
+	public void shouldCountVotes() {
+		Feedback f = new Feedback(2, 4, 8, 16);
+
+		int expected = 30;
+		int actual = f.getCount();
+
+		assertEquals(expected, actual);
+
+	}
 }

src/test/java/de/thm/arsnova/service/FeedbackServiceTest.java

@@ -3,6 +3,8 @@ package de.thm.arsnova.service;
 import de.thm.arsnova.event.DeleteFeedbackForRoomsEvent;
 import de.thm.arsnova.model.Feedback;
 import de.thm.arsnova.model.Room;
+import de.thm.arsnova.web.exceptions.NoContentException;
+import de.thm.arsnova.web.exceptions.NotFoundException;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -17,9 +19,9 @@ import java.util.List;
 import java.util.Map;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.fail;
 import static org.mockito.ArgumentMatchers.*;
-import static org.mockito.Mockito.verify;
-import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.*;
 
 @RunWith(MockitoJUnitRunner.StrictStubs.class)
 public class FeedbackServiceTest {
@@ -42,7 +44,8 @@ public class FeedbackServiceTest {
 		this.room = new Room();
 		room.setId(this.roomId);
 
-		when(this.roomService.get(this.roomId)).thenReturn(room);
+		lenient().when(this.roomService.get(anyString())).thenReturn(null);
+		lenient().when(this.roomService.get(eq(this.roomId))).thenReturn(room);
 
 		FeedbackStorageService fss = new FeedbackStorageServiceImpl();
 		this.feedbackService = new FeedbackServiceImpl(fss, this.roomService);
@@ -70,6 +73,16 @@ public class FeedbackServiceTest {
 		assertEquals(expected, actual, 0.01);
 	}
 
+	@Test(expected = NoContentException.class)
+	public void averageCalculationShouldThrowNoContentExceptionWhenNoFeedbackIsPresent() {
+		feedbackService.calculateAverageFeedback(roomId);
+	}
+
+	@Test(expected = NotFoundException.class)
+	public void averageCalculationShouldThrowNotFoundExceptionWhenRoomIsUnknown() {
+		feedbackService.calculateAverageFeedback("room-id-does-not-exist");
+	}
+
 	@Test
 	public void shouldReturnCompleteFeedbackEntity() {
 		feedbackService.save(roomId, 0, "user-id-one");