Okay as you added output of array.
You can use the following to get the result. This will print the value of test
meta key.
<button><?php $my_meta = get_post_meta( $post->ID, 'test', true ); echo $my_meta["test"]; ?></button>
if your meta key is custom-name
then you can get it like this.
<?php $my_meta = get_post_meta( $post->ID, 'custom-name', true ); echo $my_meta["custom-name"]; ?>