Properly selecting and filtering elements in variable HTML structure with jQuery

I have a HTML fragment with multiple elements (mostly of the same type (here for example I use SPAN), but also a few others) that may be enclosed within a DIV, but not always. Basically, sometimes I have a single root element (the DIV), sometimes I have multiple elements at the same level. What is the proper way to select all of these specified elements (SPAN) with jQuery?

Clarification Update: This way of selecting should succeed for both cases listed below

To give an example, the following code segment shows you two possible structures for my HTML fragment.

var test1 = "<div><span></span><span></span>开发者_JAVA技巧;<div></div></div>";
var test2 = "<span></span><span></span><div></div>";
alert($(test1).filter("span").length);
alert($(test2).filter("span").length);

Naturally, the first filter returns 0, whereas the second returns 2. I know one way to 'solve' this would be to encapsulate my fragment within a DIV, on which I then run my filter, however I'm curious to know if there's a better solution.

Update 2: What I could do (as mentioned in the paragraph above) is something like the following code, which works for both cases:

alert($("<div></div>").append(test2).find("span").length);

If you wanted to find out how many spans are contained in a element you would use

.siblings()

so say you have this:

<div><span></span><span></span><div></div></div>

if you want to see how many spans are contained in the div you would

$('div').siblings("span").length;

and if you just wanted to know how many elements are contained in that div you would just remove the parameter from siblings like this:

$('div').siblings().length;