在學(xué)習(xí)jquery1.72源代碼的sizzle模塊過程中，看不懂第5200行源代碼

源代碼這樣

        // Check to see if it's possible to do matchesSelector
        // on a disconnected node (IE 9 fails this)
        var disconnectedMatch = !matches.call( document.createElement( "div" ), "div" ),
            pseudoWorks = false;

        try {
            // This should fail with an exception
            // Gecko does not error, returns false instead
            matches.call( document.documentElement, "[test!='']:sizzle" );

        } catch( pseudoError ) {
            pseudoWorks = true;
        }

第5200行代碼matches.call( document.documentElement, "[test!='']:sizzle" )看不懂，"[test!='']:sizzle"是css選擇器的寫法嗎，test是屬性，sizzle是偽類嗎？。。。