do_shortcode inside shortcode

shortcode-from-editor.php

/*
Parses shortcodes inside shortcodes by passing the content into do_shortcode.

[testouter][testinner][/testinner][/testouter]
*/

function shortcode_test_outer( $atts, $content = null ) {
	?><p>shortcode-outer-start</p><?php
	do_shortcode( $content );
	?><p>shortcode-outer-end</p><?php
}
add_shortcode( 'testouter', 'shortcode_test_outer' );

function shortcode_test_inner( $atts, $content = null ) {
	?><p>shortcode-inner-start</p><?php
	do_shortcode( $content );
	?><p>shortcode-inner-end</p><?php
}
add_shortcode( 'testinner', 'shortcode_test_inner' );

shortcode-hard-coded.php

/*
Parses a hardcoded shortcode inside another shortcode by passing the shortcode string to do_shortcode.

[testouter][/testouter]
*/

function shortcode_test_outer( $atts, $content = null ) {
	?><p>shortcode-outer-start</p><?php
	do_shortcode( '[testinner][/testinner]' );
	?><p>shortcode-outer-end</p><?php
}
add_shortcode( 'testouter', 'shortcode_test_outer' );

function shortcode_test_inner( $atts, $content = null ) {
	?><p>shortcode-inner-start</p><?php
	?><p>shortcode-inner-end</p><?php
}
add_shortcode( 'testinner', 'shortcode_test_inner' );