db.a.drop();
for(i=0;i<25000;i++) { db.a.insert({x:i, y:"asdfasdfasdfasdfasdfasdfasdfasdfasdf"}); }
db.adminCommand('fsync'); // force checkpoint
var collectionSize = db.a.stats().storageSize;
print("coll size: " + collectionSize);

print("Remove all docs...");
db.a.remove({});
db.adminCommand('fsync'); // force checkpoint
print("table size: " + db.a.stats().storageSize);

print("Run 1st compact...");
db.a.runCommand('compact');
db.adminCommand('fsync'); // force checkpoint
print("table size: " + db.a.stats().storageSize);

assert.gt(collectionSize, db.a.stats().storageSize, "collection size should be smaller after compact");