diff --git a/tests/phpunit/tests/user/updateUserCaches.php b/tests/phpunit/tests/user/updateUserCaches.php
new file mode 100644
index 0000000000..98d14a6248
--- /dev/null
+++ b/tests/phpunit/tests/user/updateUserCaches.php
@@ -0,0 +1,53 @@
+<?php
+
+/**
+ * @group user
+ */
+class Tests_User_UpdateUserCaches extends WP_UnitTestCase {
+	public function test_should_store_entire_database_row_in_users_bucket() {
+		global $wpdb;
+
+		$u = $this->factory->user->create();
+		$raw_userdata = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->users WHERE ID = %d", $u ) );
+
+		update_user_caches( $raw_userdata );
+
+		$this->assertEquals( $raw_userdata, wp_cache_get( $u, 'users' ) );
+	}
+
+	public function test_should_store_user_id_in_userlogins_bucket() {
+		$data = new stdClass();
+		$data->ID = 12345;
+		$data->user_login = 'foo';
+		$data->user_email = 'foo@example.com';
+		$data->user_nicename = 'bar';
+
+		update_user_caches( $data );
+
+		$this->assertEquals( 12345, wp_cache_get( 'foo', 'userlogins' ) );
+	}
+
+	public function test_should_store_user_id_in_useremail_bucket() {
+		$data = new stdClass();
+		$data->ID = 12345;
+		$data->user_login = 'foo';
+		$data->user_email = 'foo@example.com';
+		$data->user_nicename = 'bar';
+
+		update_user_caches( $data );
+
+		$this->assertEquals( 12345, wp_cache_get( 'foo@example.com', 'useremail' ) );
+	}
+
+	public function test_should_store_user_id_in_userslugs_bucket() {
+		$data = new stdClass();
+		$data->ID = 12345;
+		$data->user_login = 'foo';
+		$data->user_email = 'foo@example.com';
+		$data->user_nicename = 'bar';
+
+		update_user_caches( $data );
+
+		$this->assertEquals( 12345, wp_cache_get( 'bar', 'userslugs' ) );
+	}
+}