Why does this assert.throws test not pass?

The app code:

Global = {
    setCompValue : function( comp, value ){
        if( comp === undefined ){
            console.trace();
            console.error( value );
            throw new Error( 'comp is undefined' );
        }
        ...

The QUnit test:

QUnit.test( 'Global.setCompValue called with undefined comp should throw error',
    function( assert ){
        assert.throws( Global.setCompValue( undefined, 0 ) );
});

I can see the trace and error printout in the console. But the test fails:

Died on test #1 @http://localhost/formsFor_testing/tests/global_tests.js:17:7

Edit
It was suggested that this question might help. But in fact following that answer I seem to find a false positive: the test passes even when the line throwing the error is commented out.

But I did find this answer useful... leading me to do this:

assert.throws( function(){ Global.setCompValue( undefined, 0 ) }, new Error( 'comp is undefined' ) );

... which appears not to produce false positives.