[Libguestfs] [PATCH nbdkit] s3: Only run the tests if boto3 is installed

[Laszlo Ersek]

On 05/17/22 10:55, Richard W.M. Jones wrote:
> ERROR: S3 (unittest.loader._FailedTest)
> ----------------------------------------------------------------------
> ImportError: Failed to import test module: S3
> Traceback (most recent call last):
>   File "/usr/lib64/python3.10/unittest/loader.py", line 154, in loadTestsFromName
>     module = __import__(module_name)
>   File "/home/rjones/d/nbdkit/plugins/S3/S3.py", line 41, in <module>
>     import boto3
> ModuleNotFoundError: No module named 'boto3'
> 
> Reported-by: Laszlo Ersek
> Fixes: commit 5130c43bc1f9
> ---
>  tests/test-S3-unit.sh | 1 +
>  tests/test-S3.sh      | 1 +
>  2 files changed, 2 insertions(+)
> 
> diff --git a/tests/test-S3-unit.sh b/tests/test-S3-unit.sh
> index 6b6adf02..8a32dd4c 100755
> --- a/tests/test-S3-unit.sh
> +++ b/tests/test-S3-unit.sh
> @@ -37,6 +37,7 @@ set -x
>  
>  requires $PYTHON --version
>  requires $PYTHON -c 'import unittest'
> +requires $PYTHON -c 'import boto3'
>  
>  # Python has proven very difficult to valgrind, therefore it is disabled.
>  if [ "$NBDKIT_VALGRIND" = "1" ]; then
> diff --git a/tests/test-S3.sh b/tests/test-S3.sh
> index de94751e..e51ef2ac 100755
> --- a/tests/test-S3.sh
> +++ b/tests/test-S3.sh
> @@ -36,6 +36,7 @@ set -x
>  
>  requires hexdump --version
>  requires $PYTHON --version
> +requires $PYTHON -c 'import boto3'
>  requires nbdcopy --version
>  requires_plugin python
>  
> 

This was my very first idea too, but does it not conflict with having a
fake boto3 module too, at "tests/test-S3/boto3"?

In particular, "tests/test-S3.sh" already contains:

  # There is a fake boto3 module in test-S3/ which we use as a test
  # harness for the plugin.
  requires test -d test-S3
  export PYTHONPATH=$srcdir/test-S3:$PYTHONPATH

In other words, if you added the new line

  requires $PYTHON -c 'import boto3'

to the same file, but under the PYTHONPATH extension, then I *think* the
new "requires" would succeed, but the test case would fail the same way
-- because the fake module does not expose the new exception type.

Of course I'm also 100% fine if we make both test cases dependent on the
*real* boto3 module, but should we then eliminate the "test-S3"
directory? (The fake module, that is?)

Thanks
Laszlo