diff --git a/tests/phpunit/tests/user.php b/tests/phpunit/tests/user.php
index 419e8c3..71acceb 100644
--- a/tests/phpunit/tests/user.php
+++ b/tests/phpunit/tests/user.php
@@ -145,6 +145,46 @@ class Tests_User extends WP_UnitTestCase {
 		}
 	}
 
+	/**
+	 * Test the magic __unset method
+	 *
+	 * @ticket 20043
+	 */
+	public function test_user_unset() {
+		// New user
+		$user_id = $this->factory->user->create( array( 'role' => 'author' ) );
+		$user = new WP_User( $user_id );
+
+		// Test custom fields
+		$user->customField = 123;
+		$this->assertEquals( $user->customField, 123 );
+		unset( $user->customField );
+		$this->assertFalse( isset( $user->customField ) );
+		return $user;
+	}
+
+	/**
+	 * @depends test_user_unset
+	 * @expectedDeprecated WP_User->id
+	 * @ticket 20043
+	 */
+	function test_user_unset_lowercase_id( $user ) {
+		// Test 'id' (lowercase)
+		unset( $user->id );
+		return $user;
+	}
+
+	/**
+	 * @depends test_user_unset_lowercase_id
+	 * @ticket 20043
+	 */
+	function test_user_unset_uppercase_id( $user ) {
+		// Test 'ID'
+		$this->assertNotEmpty( $user->ID );
+		unset( $user->ID );
+		$this->assertEmpty( $user->ID );
+	}
+
 	// Test meta property magic functions for property get/set/isset.
 	function test_user_meta_properties() {
 		global $wpdb;