[RFC PATCH v2 3/7] tests: Remove spurious pip warnings on Ubuntu20.04

[John Snow <jsnow@redhat.com>]

The version of pip ("20.0.2") that ships with Ubuntu 20.04 has a bug
where it will try to attempt building a wheel even if the "wheel" python
package that enables it to do so is not installed. Even though pip
continues gracefully from source, The result is a lot of irrelevant
failure output.

Upstream pip 20.0.2 does not have this problem, and pip 20.1 introduces
a new info message that informs a user that wheel building is being skipped.

On this version, the output can be silenced by passing --no-binary to
coax pip into skipping that step to begin with. Note, this error does
not seem to show up for the "qemu" package because we install that
package in editable mode. (I think, but did not test, that installing an
empty package in editable mode caused more problems than it fixed.)

Signed-off-by: John Snow <jsnow@redhat.com>
---
 tests/mkvenv.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tests/mkvenv.py b/tests/mkvenv.py
index 0667106d6aa..78f8d0382e0 100644
--- a/tests/mkvenv.py
+++ b/tests/mkvenv.py
@@ -144,7 +144,8 @@ def make_qemu_venv(
     with enter_venv(venv_path):
         if do_initialize:
             install("-e", str(pysrc_path), offline=offline)
-            install(str(test_src_path), offline=offline)
+            install("--no-binary", "qemu.dummy-tests",
+                    str(test_src_path), offline=offline)
             venv_path.touch()
 
         for option in options:
-- 
2.34.3