Add unit tests to test array inclusion and exclusion

test/queries.js

@@ -397,10 +397,11 @@ test('populate the response', async t => {
 	});
 });
 
-test('find documents and include only selected fields', async t => {
+test('find documents and include only one selected field', async t => {
 	let post = new Post({
 		title: 'San Francisco',
-		featured: true
+		featured: true,
+		published: false
 	});
 
 	await post.save();
@@ -411,17 +412,48 @@ test('find documents and include only selected fields', async t => {
 	t.same(keys, ['_id', 'title']);
 });
 
-test('find documents and exclude selected fields', async t => {
+test('find documents and include only two selected fields', async t => {
 	let post = new Post({
 		title: 'San Francisco',
-		featured: true
+		featured: true,
+		published: false
+	});
+
+	await post.save();
+
+	let posts = await Post.include(['title', 'featured']).find();
+	let attrs = posts[0].toJSON();
+	let keys = Object.keys(attrs);
+	t.same(keys, ['_id', 'title', 'featured']);
+});
+
+test('find documents and exclude one selected field', async t => {
+	let post = new Post({
+		title: 'San Francisco',
+		featured: true,
+		published: false
 	});
 
 	await post.save();
 
 	let posts = await Post.exclude('title').find();
 	let attrs = posts[0].toJSON();
 	let keys = Object.keys(attrs);
+	t.same(keys, ['_id', 'featured', 'published', 'created_at', 'updated_at']);
+});
+
+test('find documents and exclude two selected fields', async t => {
+	let post = new Post({
+		title: 'San Francisco',
+		featured: true,
+		published: false
+	});
+
+	await post.save();
+
+	let posts = await Post.exclude(['title', 'published']).find();
+	let attrs = posts[0].toJSON();
+	let keys = Object.keys(attrs);
 	t.same(keys, ['_id', 'featured', 'created_at', 'updated_at']);
 });