Actually, I met the same question as you asked in hexojs/hexo#2201.
I want to insert a code file as a collapsed spoiler and it seems difficult to deal with nesting macros. Is there any way to render something like below?

{% spoiler site_config.yml %}

{% codeblock test lang:yml %}
{% include _config.yml %}
{% endcodeblock %}

{% endspoiler %}

I'm getting this error when I added {% include 'pathtofile/file.html' %} in one of my post.
I'm at lost of where this came from. Is it something wrong with my nunjucks or is it not finding the file from path?

Template render error: (unknown path)
  Error: template not found: pathtofile/file.html
    at Object._prettifyError (...blog/node_modules/nunjucks/src/lib.js:36:11)
    at ...blog/node_modules/nunjucks/src/environment.js:561:19
...

I want to include a Markdown file from another Markdown file:

• My root Markdown file is located in src/error-ts/index.md
• I want to embed another file from src/error-ts/test.md.

Your documentation says that all file paths are relative to the source directory, so I tried the following embed:

{% include error-ts/test.md %}

This causes the error below:

err: Template render error: (unknown path)
Error: template names must be a string: Na

That's why I tried a relative path:

{% include ./error-ts/test.md %}

This caused a new error:

err: Error [Nunjucks Error]: error-ts/index.md 
[Line 4, Column 12] unexpected token: .

Here is what my src/error-ts/test.md looks like:

console.log('Hello, World!');

How can I embed it?