IDLE uses tkinter.widget.bell() in various places to signal an exceptional situation.  Examples include 'Find' when the target cannot be found and 'Expand word' when there is no expansion (or are no more expansions.

[The tk manual page is http://www.tcl.tk/man/tcl8.6/TkCmd/bell.htm.  I have no idea what difference it makes which window the bell is rung on.

When running test_idle, there are about 5 beeps.  They serve no purpose and can only discourage buildbot owners from running gui tests, even if they could.  Test_tk and test_ttk_guionly are silent.

A solution is to replace something like 'self.text.bell' with 'self.bell', where the latter is either the former or 'lambda: None', depending on a 'utest=False' parameter.

The replacement could lead to the following bonus in a follow-on issue: a separate function could be augmented to emit a 'visual bell', a signal that is seen rather than heard.  This would benefit both the hard-of-hearing and those who edit with sound turned off or redirected to headphones not worn.  Notepad++ somehow flashes the Search dialog title bar as well a adding a message to the status bar.  I would rather flash (blink) the text not found or expanded.  The idea is to replace a hard-coded external function with a custom wrapper subject to future improvement.