empty($_POST) === FALSE doesn't work as it should

I was testing the empty function in php, but it doesn't work, because the if statement is accessible whether the condition is false or true.

<?php
    if(empty($_POST) === false){

        echo 'text';
}
?>



<form action="index.php"  method="post">
    Username:
    <input type="text" name="text">
    <input type="submit" name="submit">
</form>

The echo is executed even if the input is empty.

Why ??