text: // Check that shard selection does not assert for certain unsatisfiable queries.
  // SERVER-4554, SERVER-4914
  
  s = new ShardingTest({name: 'shard7', shards: 2});
  
  db = s.admin._mongo.getDB( 'test' );
  c = db[ 'foo' ];
  c.drop();
  
  s.adminCommand( { enablesharding: '' + db } );
  s.ensurePrimaryShard(db.getName(), 'shard0001');
  s.adminCommand( { shardcollection: '' + c, key: { a:1,b:1 } } );
  
  // Check query operation with some satisfiable and unsatisfiable queries.
  
  assert.eq( 0, c.find({a:1}).itcount() );
  assert.eq( 0, c.find({a:1,b:1}).itcount() );
  assert.eq( 0, c.find({a:{$gt:4,$lt:2}}).itcount() );
  assert.eq( 0, c.find({a:1,b:{$gt:4,$lt:2}}).itcount() );
  assert.eq( 0, c.find({a:{$gt:0,$lt:2},b:{$gt:4,$lt:2}}).itcount() );
  assert.eq( 0, c.find({b:{$gt:4,$lt:2}}).itcount() );
  assert.eq( 0, c.find({a:{$in:[]}}).itcount() );
  assert.eq( 0, c.find({a:1,b:{$in:[]}}).itcount() );
  
  assert.eq( 0, c.find({$or:[{a:{$gt:0,$lt:10}},{a:12}]}).itcount() );
  assert.eq( 0, c.find({$or:[{a:{$gt:0,$lt:10}},{a:5}]}).itcount() );
  assert.eq( 0, c.find({$or:[{a:1,b:{$gt:0,$lt:10}},{a:1,b:5}]}).itcount() );
  
  // Check other operations that use getShardsForQuery.
  
  unsatisfiable = {a:1,b:{$gt:4,$lt:2}};
  
  assert.eq( 0, c.count(unsatisfiable) );
  assert.eq( [], c.distinct('a',unsatisfiable) );
  
  aggregate = c.aggregate( { $match:unsatisfiable } );
  assert.eq( 0, aggregate.toArray().length );
  
  c.save( {a:null,b:null} );
  c.save( {a:1,b:1} );
  assert.writeOK( c.remove( unsatisfiable ));
  assert.eq( 2, c.count() );
  assert.writeOK( c.update( unsatisfiable, {$set:{c:1}}, false, true ));
  assert.eq( 2, c.count() );
  assert.eq( 0, c.count( {c:1} ) );
  
  c.ensureIndex( {loc:'2d'} );
  c.save( {a:2,b:2,loc:[0,0]} );
  near = db.runCommand( {geoNear:'foo', near:[0,0], query:unsatisfiable} );
  assert.commandWorked( near );
  assert.eq( 0, near.results.length );
  