diff --git tests/phpunit/tests/image/functions.php tests/phpunit/tests/image/functions.php
index e149a32..9d7b475 100644
--- tests/phpunit/tests/image/functions.php
+++ tests/phpunit/tests/image/functions.php
@@ -30,8 +30,6 @@ class Tests_Image_Functions extends WP_UnitTestCase {
 		if ( extension_loaded( 'fileinfo' ) ) {
 			$finfo = new finfo();
 			$mime_type = $finfo->file( $filename, FILEINFO_MIME );
-		} elseif ( function_exists( 'mime_content_type' ) ) {
-			$mime_type = mime_content_type( $filename );
 		}
 		if ( false !== strpos( $mime_type, ';' ) ) {
 			list( $mime_type, $charset ) = explode( ';', $mime_type, 2 );
@@ -112,7 +110,7 @@ class Tests_Image_Functions extends WP_UnitTestCase {
 	 * @ticket 6821
 	 */
 	public function test_wp_save_image_file() {
-		if ( ! extension_loaded( 'fileinfo' ) && ! function_exists( 'mime_content_type' ) ) {
+		if ( ! extension_loaded( 'fileinfo' ) ) {
 			$this->markTestSkipped( 'The fileinfo PHP extension is not loaded.' );
 		}
 
@@ -160,7 +158,7 @@ class Tests_Image_Functions extends WP_UnitTestCase {
 	 * @ticket 6821
 	 */
 	public function test_mime_overrides_filename() {
-		if ( ! extension_loaded( 'fileinfo' ) && ! function_exists( 'mime_content_type' ) ) {
+		if ( ! extension_loaded( 'fileinfo' ) ) {
 			$this->markTestSkipped( 'The fileinfo PHP extension is not loaded.' );
 		}
 
@@ -198,7 +196,7 @@ class Tests_Image_Functions extends WP_UnitTestCase {
 	 * @ticket 6821
 	 */
 	public function test_inferred_mime_types() {
-		if ( ! extension_loaded( 'fileinfo' ) && ! function_exists( 'mime_content_type' ) ) {
+		if ( ! extension_loaded( 'fileinfo' ) ) {
 			$this->markTestSkipped( 'The fileinfo PHP extension is not loaded.' );
 		}