t = db.geo3
t.drop();

n = 1
for ( var x=-100; x<100; x+=2 ){
    for ( var y=-100; y<100; y+=2 ){
        t.insert( { _id : n++ , loc : [ x , y ] , a : Math.abs( x ) % 5 , b : Math.abs( y ) % 5 } )
    }
}


t.ensureIndex( { loc : "2d" } )

fast = db.runCommand( { geoNear : t.getName() , near : [ 50 , 50 ] , num : 10 } );

//printjson( fast.stats );

slow = db.runCommand( { geoNear : t.getName() , near : [ 50 , 50 ] , num : 10 , start : "11" } );

printjson( slow.stats );

assert.lt( fast.stats.nscanned * 10 , slow.stats.nscanned , "A1" );
assert.lt( fast.stats.objectsLoaded , slow.stats.objectsLoaded , "A2" );
assert.eq( fast.stats.avgDistance , slow.stats.avgDistance , "A3" );

// test filter

filtered1 = db.runCommand( { geoNear : t.getName() , near : [ 50 , 50 ] , num : 10 , query : { a : 2 } } );
assert.eq( 10 , filtered1.results.length , "B1" );
filtered1.results.forEach( function(z){ assert.eq( 2 , z.obj.a , "B2: " + tojson( z ) ); } )
//printjson( filtered1.stats );

function avgA( q , len ){
    if ( ! len )
        len = 10;
    var realq = { loc : { $near : [ 50 , 50 ] } };
    if ( q )
        Object.extend( realq , q );
    var as = 
        t.find( realq ).limit(len).map( 
            function(z){ 
                return z.a; 
            }
        );
    assert.eq( len , as.length , "length in avgA" );
    return Array.avg( as );
}

function testFiltering( msg ){
    assert.gt( 2 , avgA( {} ) , msg + " testFiltering 1 " );
    assert.eq( 2 , avgA( { a : 2 } ) , msg + " testFiltering 2 " );
    assert.eq( 4 , avgA( { a : 4 } ) , msg + " testFiltering 3 " );
}

testFiltering( "just loc" );

t.dropIndex( { loc : "2d" } )
assert.eq( 1 , t.getIndexKeys().length , "setup 3a" )
t.ensureIndex( { loc : "2d" , a : 1 } )
assert.eq( 2 , t.getIndexKeys().length , "setup 3b" )

filtered2 = db.runCommand( { geoNear : t.getName() , near : [ 50 , 50 ] , num : 10 , query : { a : 2 } } );
assert.eq( 10 , filtered2.results.length , "B3" );
filtered2.results.forEach( function(z){ assert.eq( 2 , z.obj.a , "B4: " + tojson( z ) ); } )

assert.eq( filtered1.stats.avgDistance , filtered2.stats.avgDistance , "C1" )
assert.eq( filtered1.stats.nscanned , filtered2.stats.nscanned , "C3" )
assert.gt( filtered1.stats.objectsLoaded , filtered2.stats.objectsLoaded , "C3" )

testFiltering( "loc and a" );

t.dropIndex( { loc : "2d" , a : 1 } )
assert.eq( 1 , t.getIndexKeys().length , "setup 4a" )
t.ensureIndex( { loc : "2d" , b : 1 } )
assert.eq( 2 , t.getIndexKeys().length , "setup 4b" )

testFiltering( "loc and b" );


q = { loc : { $near : [ 50 , 50 ] } }
assert.eq( 100 , t.find( q ).limit(100).itcount() , "D1" )
assert.eq( 100 , t.find( q ).limit(100).count() , "D2" )

assert.eq( 20 , t.find( q ).limit(20).itcount() , "D3" )
assert.eq( 20 , t.find( q ).limit(20).size() , "D4" )