BAEL-5416 How to Store HashMap<String, ArrayList> Inside a List (#12047)

* add unit test

* fix the error

* correcting the name of the test

* trigger build process

core-java-modules/core-java-collections-list/src/test/java/com/baeldung/list/listOfHashMaps/ListOfHashMapsUnitTest.java

@@ -0,0 +1,36 @@
+package test.java.com.baeldung.list.listOfHashMaps;
+
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static org.junit.Assert.assertTrue;
+
+public class ListOfHashMapsUnitTest {
+    List<HashMap<String, List<String>>> booksAuthorsMapsList = new ArrayList<>();
+
+    @Test
+    public void givenMaps_whenAddToList_thenListContainsMaps() {
+        HashMap<String, List<String>> javaBooksAuthorsMap = new HashMap<>();
+        HashMap<String, List<String>> phpBooksAuthorsMap = new HashMap<>();
+        javaBooksAuthorsMap.put("Head First Java", Arrays.asList("Kathy Sierra", "Bert Bates"));
+        javaBooksAuthorsMap.put("Effective Java", Arrays.asList("Joshua Bloch"));
+        javaBooksAuthorsMap.put("OCA Java SE 8",
+                Arrays.asList("Kathy Sierra", "Bert Bates", "Elisabeth Robson"));
+        phpBooksAuthorsMap.put("The Joy of PHP", Arrays.asList("Alan Forbes"));
+        phpBooksAuthorsMap.put("Head First PHP &amp; MySQL",
+                Arrays.asList("Lynn Beighley", "Michael Morrison"));
+
+        booksAuthorsMapsList.add(javaBooksAuthorsMap);
+        booksAuthorsMapsList.add(phpBooksAuthorsMap);
+
+        assertTrue(booksAuthorsMapsList.get(0).keySet().containsAll
+                (javaBooksAuthorsMap.keySet().stream().collect(Collectors.toList())));
+        assertTrue(booksAuthorsMapsList.get(1).keySet().containsAll
+                (phpBooksAuthorsMap.keySet().stream().collect(Collectors.toList())));
+    }
+}