This commit is for the article BAEL-6792 (#14512)

This commit aims to add a test class namely (StringToMapUnitTest) that tests the conversion of string and string array into map.

core-java-modules/core-java-collections-maps-6/src/test/java/com/baeldung/strringtomap/StringToMapUnitTest.java

@@ -0,0 +1,89 @@
+package com.baeldung.stringtomap;
+
+import org.junit.Test;
+
+import java.util.*;
+
+import static org.junit.Assert.assertEquals;
+
+public class StringToMapUnitTest {
+
+    public Map<String, String> convertStringToMap(String data) {
+        Map<String, String> map = new HashMap<>();
+        StringTokenizer tokenizer = new StringTokenizer(data, " ");
+
+        while (tokenizer.hasMoreTokens()) {
+            String token = tokenizer.nextToken();
+            String[] keyValue = token.split("=");
+            map.put(keyValue[0], keyValue[1]);
+        }
+
+        return map;
+    }
+
+    @Test
+    public void given_StringWithKeyValuePairs_whenUsing_convertStringToMap_thenMapCreated() {
+        String data = "name=John age=30 city=NewYork";
+        Map<String, String> expectedMap = new HashMap<>();
+        expectedMap.put("name", "John");
+        expectedMap.put("age", "30");
+        expectedMap.put("city", "NewYork");
+        Map<String, String> resultMap = convertStringToMap(data);
+        assertEquals(expectedMap, resultMap);
+    }
+
+    public Map<String, String> convertStringArrayToMap(String[] data) {
+        Map<String, String> map = new HashMap<>();
+
+        for (String keyValue : data) {
+            String[] parts = keyValue.split("=");
+            map.put(parts[0], parts[1]);
+        }
+
+        return map;
+    }
+
+    @Test
+    public void given_StringArrayWithKeyValuePairs_whenUsing_convertStringArrayToMap_thenMapCreated() {
+        String[] data = {"name=John", "age=30", "city=NewYork"};
+        Map<String, String> expectedMap = new HashMap<>();
+        expectedMap.put("name", "John");
+        expectedMap.put("age", "30");
+        expectedMap.put("city", "NewYork");
+        Map<String, String> resultMap = convertStringArrayToMap(data);
+        assertEquals(expectedMap, resultMap);
+    }
+
+    public Map<String, List<String>> convertStringArrayToMapWithDuplicates(String[] data) {
+        Map<String, List<String>> map = new HashMap<>();
+
+        for (String keyValue : data) {
+            String[] parts = keyValue.split("=");
+            String key = parts[0];
+            String value = parts[1];
+
+            if (map.containsKey(key)) {
+                List<String> valuesList = map.get(key);
+                valuesList.add(value);
+            } else {
+                List<String> valuesList = new ArrayList<>();
+                valuesList.add(value);
+                map.put(key, valuesList);
+            }
+        }
+
+        return map;
+
+    }
+
+    @Test
+    public void given_StringArrayWithKeyValuePairsWithDuplicates_whenUsing_convertStringArrayToMapWithDuplicates_thenMapCreatedWithLists() {
+        String[] data = {"name=John", "age=30", "city=NewYork", "age=31"};
+        Map<String, List<String>> expectedMap = new HashMap<>();
+        expectedMap.put("name", Collections.singletonList("John"));
+        expectedMap.put("age", Arrays.asList("30", "31"));
+        expectedMap.put("city", Collections.singletonList("NewYork"));
+        Map<String, List<String>> resultMap = convertStringArrayToMapWithDuplicates(data);
+        assertEquals(expectedMap, resultMap);
+    }
+}