30_lines_to_test.js

function pass() { console.count('pass'); }
function fail(expr, msg) {
  console.count('fail')
  console.warn((msg||'')+'expected true got', expr);
}
function assert(expr, msg) {
  try {
    var result = expr();
    if(result) pass();
    else fail(result, msg);
  }
  catch(e) {
    console.count('error')
    console.error(e.message);
    console.info('while running');
    console.log(expr.toString());
  }
}

assert(function(){
  return false;
});

assert(function() {
  return true;
});

assert(function() {
  return gdangle;
});