Index: tests/functions.php
===================================================================
--- tests/functions.php	(revision 972)
+++ tests/functions.php	(working copy)
@@ -324,4 +324,58 @@
 
 		$_SERVER['REQUEST_URI'] = $old_req_uri;
 	}
+
+	function test_get_allowed_mime_types() {
+		$mimes = get_allowed_mime_types();
+
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		$callback = function( $mimes ) {
+			return array();
+		};
+
+		add_filter( 'upload_mimes',  $callback );
+		$mimes = get_allowed_mime_types();
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertEmpty( $mimes );
+
+		remove_filter( 'upload_mimes', $callback );
+		$mimes = get_allowed_mime_types();
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertNotEmpty( $mimes );
+	}
+
+	function test_wp_get_mime_types() {
+		$mimes = wp_get_mime_types();
+
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		$callback = function( $mimes ) {
+			return array();
+		};
+
+		add_filter( 'mime_types',  $callback );
+		$mimes = wp_get_mime_types();
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertEmpty( $mimes );
+
+		remove_filter( 'mime_types', $callback );
+		$mimes = wp_get_mime_types();
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		// upload_mimes shouldn't affect wp_get_mime_types()
+		add_filter( 'upload_mimes',  $callback );
+		$mimes = wp_get_mime_types();
+		$this->assertInternalType( 'array', $mimes );
+		$this->assertNotEmpty( $mimes );
+
+		remove_filter( 'upload_mimes', $callback );
+		$mimes2 = wp_get_mime_types();
+		$this->assertInternalType( 'array', $mimes2 );
+		$this->assertNotEmpty( $mimes2 );
+		$this->assertEquals( $mimes2, $mimes );
+	}
 }