[PATCH v2 1/3] tests/functional: enable force refresh of cached assets

["Daniel P. Berrangé" <berrange@redhat.com>]

If the 'QEMU_TEST_REFRESH_CACHE' environment variable is set, then
ignore any existing cached asset and download a fresh copy.

This can be used to selectively refresh assets if set before running
a single test script.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 docs/devel/testing/functional.rst   | 3 +++
 tests/functional/qemu_test/asset.py | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/docs/devel/testing/functional.rst b/docs/devel/testing/functional.rst
index 3728bab6c0..fdeaebaadc 100644
--- a/docs/devel/testing/functional.rst
+++ b/docs/devel/testing/functional.rst
@@ -312,6 +312,9 @@ The cache is populated in the ``~/.cache/qemu/download`` directory by
 default, but the location can be changed by setting the
 ``QEMU_TEST_CACHE_DIR`` environment variable.
 
+To force the test suite to re-download the cache, even if still valid,
+set the ``QEMU_TEST_REFRESH_CACHE`` environment variable.
+
 Skipping tests
 --------------
 
diff --git a/tests/functional/qemu_test/asset.py b/tests/functional/qemu_test/asset.py
index 704b84d0ea..b5a6136d36 100644
--- a/tests/functional/qemu_test/asset.py
+++ b/tests/functional/qemu_test/asset.py
@@ -72,6 +72,10 @@ def _check(self, cache_file):
         return self.hash == hl.hexdigest()
 
     def valid(self):
+        if os.getenv("QEMU_TEST_REFRESH_CACHE", None) is not None:
+            self.log.info("Force refresh of asset %s", self.url)
+            return False
+
         return self.cache_file.exists() and self._check(self.cache_file)
 
     def fetchable(self):
-- 
2.50.1