From 04626e522a0b5ecd0b8b033c3c850a38d73008f2 Mon Sep 17 00:00:00 2001
From: Juan Vaccari <juanvaccari@gmail.com>
Date: Wed, 23 Jan 2019 19:07:06 +0000
Subject: [PATCH] BAEL-2514 - Added unit tests for multiple values

---
 .../baeldung/stream/StreamMapUnitTest.java    | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/java-streams/src/test/java/com/baeldung/stream/StreamMapUnitTest.java b/java-streams/src/test/java/com/baeldung/stream/StreamMapUnitTest.java
index 15f1e8a517..45694bc59f 100644
--- a/java-streams/src/test/java/com/baeldung/stream/StreamMapUnitTest.java
+++ b/java-streams/src/test/java/com/baeldung/stream/StreamMapUnitTest.java
@@ -4,10 +4,13 @@ import org.junit.Before;
 import org.junit.Test;
 
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.stream.Collectors;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 public class StreamMapUnitTest {
 
@@ -62,4 +65,27 @@ public class StreamMapUnitTest {
         assertEquals(null, isbn);
     }
 
+    @Test
+    public void whenMultipleResultsVersionCalledForExistingTitle_aCollectionWithMultipleValuesIsReturned() {
+        books.put("978-0321356680", "Effective Java: Second Edition");
+
+        List<String> isbnCodes = books.entrySet().stream()
+                .filter(e -> e.getValue().startsWith("Effective Java"))
+                .map(Map.Entry::getKey)
+                .collect(Collectors.toList());
+
+        assertTrue(isbnCodes.contains("978-0321356680"));
+        assertTrue(isbnCodes.contains("978-0134685991"));
+    }
+
+    @Test
+    public void whenMultipleResultsVersionCalledForNonExistingTitle_aCollectionWithNoValuesIsReturned() {
+        List<String> isbnCodes = books.entrySet().stream()
+                .filter(e -> e.getValue().startsWith("Spring"))
+                .map(Map.Entry::getKey)
+                .collect(Collectors.toList());
+
+        assertTrue(isbnCodes.isEmpty());
+    }
+
 }