This reverts commit aab534b894 & uses the
driverInteractive attribute for the test driver instead.
This has the same effect but removes the extra module in the
nixos-build-vms code.
In 5500dc8 we introduced the --keep-vm-state flag and defaulted to that
flag not being set. This lead to the `runInMachine` tests not longer
working and that going unnoticed for quite some time now.
Previously you would be able to override only the QEMU package to be
used in the test runner. Frankly that doesn't help a lot if you are
trying to get a graphical session. The graphical session requires the
option in the NixOS module system to bet set to the correct QEMU
package.
In this commit I moved most of the test node configuration and
transformations into the `mkDriver` function (previously called
`driver`). The motivation was to be able to create a `driver` instance
with a given QEMU package that will be used consistently througout the
test expression.
According to Python documentation [0], `bufsize=1` is only meaningful in
text mode. As we don't pass in an argument called `universal_newlines`,
`encoding`, `errors` or `text` the file objects aren't opened in text
mode, which means the argument is ignored with a warning in Python 3.8.
line buffering (buffering=1) isn't supported in binary mode,
the default buffer size will be used
This commit removes this warning that appared when using
interactive test driver built with `-A driver`. This is done by
removing `bufsize=1` from Popen calls.
The default parameter when unspecified for `bufsize` is `-1` which
according to the documentation will be interpreted as
`io.DEFAULT_BUFFER_SIZE`. As mentioned by a warning, Python already
uses default buffer size when providing `buffering=1` parameter for
file objects not opened in text mode.
[0]: https://docs.python.org/3/library/subprocess.html#subprocess.Popen
