diff --git a/tests/phpunit/tests/rest-api/restAreValuesEqual.php b/tests/phpunit/tests/rest-api/restAreValuesEqual.php
new file mode 100644
index 0000000000000..360620dae203b
--- /dev/null
+++ b/tests/phpunit/tests/rest-api/restAreValuesEqual.php
@@ -0,0 +1,116 @@
+<?php
+
+/**
+ * Tests for rest_are_values_equal().
+ *
+ * @group restapi
+ *
+ * @covers ::rest_are_values_equal
+ */
+class Tests_REST_API_RestAreValuesEqual extends WP_UnitTestCase {
+
+	/**
+	 * @ticket 65819
+	 *
+	 * @dataProvider data_equal_values
+	 *
+	 * @param mixed $value1 First value.
+	 * @param mixed $value2 Second value.
+	 */
+	public function test_returns_true_for_equal_values( $value1, $value2 ) {
+		$this->assertTrue( rest_are_values_equal( $value1, $value2 ) );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array[]
+	 */
+	public static function data_equal_values() {
+		return array(
+			'same strings'                     => array( 'hello', 'hello' ),
+			'same integers'                    => array( 7, 7 ),
+			'integer and float'                => array( 1, 1.0 ),
+			'float and integer'                => array( 1.0, 1 ),
+			'same booleans'                    => array( true, true ),
+			'both null'                        => array( null, null ),
+			'same lists'                       => array( array( 1, 2 ), array( 1, 2 ) ),
+			'objects with null property'       => array(
+				array(
+					'a' => null,
+					'b' => 1,
+				),
+				array(
+					'a' => null,
+					'b' => 1,
+				),
+			),
+			'same objects different key order' => array(
+				array(
+					'a' => 1,
+					'b' => 2,
+				),
+				array(
+					'b' => 2,
+					'a' => 1,
+				),
+			),
+			'nested coercion and key order'    => array(
+				array(
+					'items' => array(
+						1,
+						array(
+							'x' => 2,
+							'y' => 3.0,
+						),
+					),
+				),
+				array(
+					'items' => array(
+						1.0,
+						array(
+							'y' => 3,
+							'x' => 2.0,
+						),
+					),
+				),
+			),
+		);
+	}
+
+	/**
+	 * @ticket 65819
+	 *
+	 * @dataProvider data_unequal_values
+	 *
+	 * @param mixed $value1 First value.
+	 * @param mixed $value2 Second value.
+	 */
+	public function test_returns_false_for_unequal_values( $value1, $value2 ) {
+		$this->assertFalse( rest_are_values_equal( $value1, $value2 ) );
+	}
+
+	/**
+	 * Data provider.
+	 *
+	 * @return array[]
+	 */
+	public static function data_unequal_values() {
+		return array(
+			'different strings'    => array( 'hello', 'world' ),
+			'string and integer'   => array( '1', 1 ),
+			'integer and float'    => array( 1, 2.0 ),
+			'float and integer'    => array( 2.0, 1 ),
+			'different list order' => array( array( 1, 2 ), array( 2, 1 ) ),
+			'different counts'     => array( array( 1 ), array( 1, 2 ) ),
+			'missing object key'   => array(
+				array( 'a' => 1 ),
+				array( 'b' => 1 ),
+			),
+			'nested mismatch'      => array(
+				array( 'items' => array( 1, 2 ) ),
+				array( 'items' => array( 1, 3 ) ),
+			),
+		);
+	}
+}