test largefile support (test_largefile.py)

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

BPO	400511
Nosy	@gvanrossum, @tim-one, @freddrake
Files	None: None

^{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: ```python assignee = None closed_at = created_at = labels = ['library'] title = 'test largefile support (test_largefile.py)' updated_at = user = 'https://bugs.python.org/tmick' ``` bugs.python.org fields: ```python activity = actor = 'tmick' assignee = 'tmick' closed = True closed_date = None closer = None components = ['Library (Lib)'] creation = creator = 'tmick' dependencies = [] files = ['2442'] hgrepos = [] issue_num = 400511 keywords = ['patch'] message_count = 9.0 messages = ['32717', '32718', '32719', '32720', '32721', '32722', '32723', '32724', '32725'] nosy_count = 4.0 nosy_names = ['gvanrossum', 'tim.peters', 'fdrake', 'tmick'] pr_nums = [] priority = 'normal' resolution = None stage = None status = 'closed' superseder = None type = None url = 'https://bugs.python.org/issue400511' versions = [] ```

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

[freddrake]

Looks good to me, and properly skips the large file test on my Linux box. A second iteration may be useful to provide separate options for different resources (cpu/disk/ram), but it's not clearly needed at this time.

Accepted as-is.

[gvanrossum]

This was accepted ages agon -- what are you waiting for?

[tim-one]

Fred, can you test this on a Linux with > 2Gb files (needs the --have-resources switch; read Trent's comment), or pass it on to someone who can? I can't do more than stare at this, and nothing in my staring hit my eye. Well, Guido may hate the long option name (--have-resources), especially given that even with all those letters \<wink>, it's not really self-describing.

[tim-one]

Fred, do something with this or assign it to some other Unix geek?

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

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[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

This patch adds a test for largefiles (creating, seeking, telling, etc.). The test skips if there is no largefile support.

There is one further problem. The test basically involves creating a file greater than 2GB and playing with it. On UN*X systems with sparse files this is no problem. On Win64 (which I have heard *can do sparse files, but not in Python yet), however, >2GB space and a *long time is required to run the test. I don't think it is reasonable to turn this on by default... so here is what I did.

I extended regrtest.py to accept the --have-resources switch. This sets test_support.use_large_resources, which is checked in test_largefile.py. By default 'use_large_resources' is false. On Win64, then, by default the largefile test is skipped but can be run via the --have-resources switch to regrtest.py or by running the test directly. This seems to me the Right Thing.

The affected files are: Lib/test/regrtest.py Lib/test/test_support.py Lib/test/test_largefile.py (new) Lib/test/output/test_largefile (new)

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

--have-at-least-2GB-on-hard-drive-and-am-going-for-coffee-\<wink>

[bdaf8532-ded6-4d4c-9bb3-51fd76040dc1]

Sorry about the delay. Had to make some small changes to get the old patch to apply.