That might be a typo, but in case you really are embedding with ![[base]], change it to ![[base.base]].
Otherwise, the filter you have looks like it would work. You could simplify it to
test == this.file
Even if you already tried that then expanded it while trying to get it to work, give it another go. If it still doesn’t work, then the issue might be something other than the filter.
Is either of those notes in an excluded folder (Files and links > Excluded files)? Or do you have multiple notes named “Source” (maybe Bases is disambiguating to the wrong file)? Or is the base already returning 15 results (the limit you set), and “Source.md” would be 16th or later?
Thank you very much for your answer and your detailed questions!!!
Wow, here is something interesting:
In my example above, I didn’t use a .base-file. Instead I used a normal note, with the base codeblock in it. That didn’t work, not with my filter above nor with your filter (test == this.file).
But if I use a .base-file with these filters, the embedded ![[base.base]] returns the Source-note.
Is that a bug in bases? the codeblock and the .base-files should work here the same way, or shouldn’t they?