Added tags CRUD operations.

persistence-modules/java-mongodb/src/test/java/com/baeldung/tagging/TaggingIntegrationTest.java

@@ -1,12 +1,14 @@
 package com.baeldung.tagging;
 
 import java.io.IOException;
+import java.util.Arrays;
 import java.util.List;
+import java.util.stream.StreamSupport;
 
-import org.junit.Before;
-import org.junit.Test;
 import org.junit.After;
 import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
 
 /**
  * Test for {@link TagRepository}.
@@ -41,7 +43,7 @@ public class TaggingIntegrationTest {
 		results.forEach(post -> {
 			Assert.assertTrue(post.getTags().contains("MongoDB"));
 		});
-		
+
 	}
 
 	/**
@@ -109,7 +111,7 @@ public class TaggingIntegrationTest {
 	public void givenTagRepository_whenPostsWithoutTagsMongoDBJava8_then0Results() {
 		List<Post> results = repository.postsWithoutTags("MongoDB", "Java 8");
 		results.forEach(System.out::println);
-		
+
 		Assert.assertEquals(0, results.size());
 		results.forEach(post -> {
 			Assert.assertFalse(post.getTags().contains("MongoDB"));
@@ -117,6 +119,51 @@ public class TaggingIntegrationTest {
 		});
 	}
 
+	/**
+	 * Tests {@link TagRepository#addTags(String, List)} and
+	 * {@link TagRepository#removeTags(String, List)}. These tests run together
+	 * to keep the database in a consistent state.
+	 */
+	@Test
+	public void givenTagRepository_whenAddingRemovingElements_thenNoDuplicates() {
+		// Adds one element and checks the result.
+		boolean result = repository.addTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertTrue(result);
+
+		// We add the same elements again to check that there's no duplication.
+		result = repository.addTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertFalse(result);
+
+		// Fetches the element back to check if the elements have been added.
+		List<Post> postsAfterAddition = repository.postsWithAllTags("jUnit", "jUnit5");
+		Assert.assertEquals(1, postsAfterAddition.size());
+		postsAfterAddition.forEach(post -> {
+			Assert.assertTrue(post.getTags().contains("jUnit"));
+			Assert.assertTrue(post.getTags().contains("jUnit5"));
+		});
+
+		// Checks for duplication.
+		long countDuplicateTags = StreamSupport.stream(postsAfterAddition.get(0).getTags().spliterator(), false)
+				.filter(x -> x.equals("jUnit5")).count();
+		Assert.assertEquals(1, countDuplicateTags);
+
+		// Tries to remove the tags added.
+		result = repository.removeTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertTrue(result);
+
+		// We remove the same elements again to check for errors.
+		result = repository.removeTags("Post 1", Arrays.asList("jUnit", "jUnit5"));
+		Assert.assertFalse(result);
+
+		// Fetches the element back to check if the elements have been removed.
+		List<Post> postsAfterDeletion = repository.postsWithAllTags("jUnit", "jUnit5");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+		postsAfterDeletion = repository.postsWithAtLeastOneTag("jUnit");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+		postsAfterDeletion = repository.postsWithAtLeastOneTag("jUnit5");
+		Assert.assertEquals(0, postsAfterDeletion.size());
+	}
+
 	/**
 	 * Cleans up the test by deallocating memory.
 	 *