The tests for the dis module can be too rigid when changing opcodes

[MaximeBelanger]

BPO	35080
Nosy	@serhiy-storchaka
PRs	bpo-35080: Tests for dis are more flexible to opcode changes #10142

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2018-10-27.05:27:14.637>
created_at = <Date 2018-10-26.23:35:56.520>
labels = ['tests', '3.8', 'type-feature', 'library']
title = 'The tests for the `dis` module can be too rigid when changing opcodes'
updated_at = <Date 2018-10-27.05:27:14.636>
user = 'https://bugs.python.org/MaximeBelanger'

bugs.python.org fields:

activity = <Date 2018-10-27.05:27:14.636>
actor = 'Maxime Belanger'
assignee = 'none'
closed = True
closed_date = <Date 2018-10-27.05:27:14.637>
closer = 'Maxime Belanger'
components = ['Library (Lib)', 'Tests']
creation = <Date 2018-10-26.23:35:56.520>
creator = 'Maxime Belanger'
dependencies = []
files = []
hgrepos = []
issue_num = 35080
keywords = ['patch']
message_count = 3.0
messages = ['328615', '328638', '328641']
nosy_count = 2.0
nosy_names = ['serhiy.storchaka', 'Maxime Belanger']
pr_nums = ['10142']
priority = 'normal'
resolution = 'wont fix'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue35080'
versions = ['Python 3.8']

[MaximeBelanger]

For various reasons, one may want to change the [Lib/opcode.py](https://github.com/python/cpython/blob/main/Lib/opcode.py) module. In doing so, this has caused us to frequently rewrite test_dis.py. It would be great if those tests used dis.opmap rather than hard-coded/magic numbers, as this would allow easier changes.

[serhiy-storchaka]

Actually this change decreases flexibility of tests. Expected output is generated. See the comment above it. When you change the bytecode, you need just uncomment these lines, run tests, copy the output, and comment out them back. The output contains numerical values of opcodes.

It is rarely they are changed without changing the meaning of opcodes. It is more common to add new opcodes and replace old opcodes with other opcodes with different semantic. This leads to changing opcode arguments and offsets, adding and removing lines.

[MaximeBelanger]

Ah, quite right; apologies for the not-so-useful PR!