[issue30303] IDLE: Add _utest to textview

[Louie Lu]

New submission from Louie Lu:

Relate to #30290, add _utest to textview to support direct unittest.

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assignee: terry.reedy
components: IDLE
messages: 293228
nosy: louielu, terry.reedy
priority: normal
severity: normal
status: open
title: IDLE: Add _utest to textview
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue30303>
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