first pair code

2020-09-08 21:04:43 +05:30
parent 976862de1a
commit b331b1779f
18 changed files with 182 additions and 499 deletions
@@ -0,0 +1,125 @@
+package com.baeldung.collections.mapfirstpair;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+
+import java.util.AbstractMap;
+import java.util.HashMap;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class MapFirstPairServiceUnitTest {
+
+    private MapFirstPairService mapFirstPairService;
+
+    @Before
+    public void Setup() {
+
+        mapFirstPairService = new MapFirstPairServiceImpl();
+    }
+
+    private void populateMapValues(Map<Integer, String> map) {
+        if (map != null) {
+            map.put(5, "A");
+            map.put(1, "B");
+            map.put(2, "C");
+        }
+    }
+
+    @Test
+    public void whenUsingIteratorForHashMap() {
+        Map<Integer, String> hashMap = new HashMap<>();
+        populateMapValues(hashMap);
+
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(hashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
+        Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+        assertNotEquals(pairInsertedFirst, actualValue);
+    }
+
+    @Test
+    public void whenUsingStreamForHashMap() {
+        Map<Integer, String> hashMap = new HashMap<>();
+        populateMapValues(hashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(hashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
+        Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+        assertNotEquals(pairInsertedFirst, actualValue);
+    }
+
+    @Test
+    public void whenUsingIteratorForLinkedHashMap() {
+        Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
+        populateMapValues(linkedHashMap);
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(linkedHashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+    }
+
+    @Test
+    public void whenUsingStreamForLinkedHashMap() {
+        Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
+        populateMapValues(linkedHashMap);
+
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(linkedHashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+    }
+
+    @Test
+    public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingIterator() {
+        Map<Integer, String> hashMap = new HashMap<>();
+        populateMapValues(hashMap);
+
+        hashMap.put(0, "D");
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(hashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
+
+        assertEquals(expectedValue, actualValue);
+    }
+
+    @Test
+    public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingStream() {
+        Map<Integer, String> hashMap = new HashMap<>();
+        populateMapValues(hashMap);
+
+        hashMap.put(0, "D");
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(hashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
+
+        assertEquals(expectedValue, actualValue);
+    }
+
+    @Test
+    public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingIterator() {
+        Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
+        populateMapValues(linkedHashMap);
+
+        linkedHashMap.put(0, "D");
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingIterator(linkedHashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+    }
+
+    @Test
+    public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingStream() {
+        Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
+        populateMapValues(linkedHashMap);
+
+        linkedHashMap.put(0, "D");
+        Map.Entry<Integer, String> actualValue = mapFirstPairService.getFirstPairUsingStream(linkedHashMap);
+        Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
+
+        assertEquals(expectedValue, actualValue);
+    }
+}