When you already have a package with a name "XXX" and you create a new class with its package name as "XXX-YYY", Pharo automatically detects "YYY" as a tag for the package and not as a new package. That is your problem. Your class TBPostTest is not in a package that ends with "-Tests". It is in "TinyBlog" package with the tag "Tests"

From: Michael Burns via Pharo-users <pharo-users@lists.pharo.org>
Sent: 24 May 2021 18:00
To: pharo-users@lists.pharo.org <pharo-users@lists.pharo.org>
Cc: Michael and Mary Burns <michaelburns@mac.com>
Subject: [Pharo-users] Creating tests for the TinyBlog tutorial

In TinyBlogEn-gitc55a88d.pdf on page 11 (2.7 Post Queries):

TestCase subclass: #TBPostTest
instanceVariableNames: ''
classVariableNames: ''
package: 'TinyBlog-Tests'

Every time I save this new class, it ends up in the TinyBlog package, not TinyBlog-Tests.

I see that many other packages have *-Tests packages where their tests live.

It seems to test OK so it�s not a stopper for me, but I get an error:
�Test class not in a package with name ending with �-Tests�"

I�d like to understand.

I�m running:

Pharo8.0.0
build: 1124, commit: 0932da8

On MacOS 11.3.1. M1 MbPro