[Qemu-block] [PATCH] iotests: Require Python 3.5 or later

[Kevin Wolf]

Running iotests is not required to build QEMU, so we can have stricter
version requirements for Python here and can make use of new features
and drop compatibility code earlier.

This makes qemu-iotests skip all Python tests if a Python version before
3.5 is used for the build.

Suggested-by: Eduardo Habkost <address@hidden>
Signed-off-by: Kevin Wolf <address@hidden>
---
 tests/qemu-iotests/check | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/tests/qemu-iotests/check b/tests/qemu-iotests/check
index 875399d79f..a68f414d6c 100755
--- a/tests/qemu-iotests/check
+++ b/tests/qemu-iotests/check
@@ -633,6 +633,13 @@ then
     export SOCKET_SCM_HELPER="$build_iotests/socket_scm_helper"
 fi
 
+# Note that if the Python conditional here evaluates True we will exit
+# with status 1 which is a shell 'false' value.
+python_usable=false
+if ! $PYTHON -c 'import sys; sys.exit(sys.version_info >= (3,5))'; then
+    python_usable=true
+fi
+
 default_machine=$($QEMU_PROG -machine help | sed -n '/(default)/ s/ .*//p')
 default_alias_machine=$($QEMU_PROG -machine help | \
    sed -n "/(alias of $default_machine)/ { s/ .*//p; q; }")
@@ -809,7 +816,12 @@ do
         start=$(_wallclock)
 
         if [ "$(head -n 1 "$source_iotests/$seq")" == "#!/usr/bin/env python" 
]; then
-            run_command="$PYTHON $seq"
+            if $python_usable; then
+                run_command="$PYTHON $seq"
+            else
+                run_command="false"
+                echo "Unsupported Python version" > $seq.notrun
+            fi
         else
             run_command="./$seq"
         fi
-- 
2.20.1