join to existing mark expr with "and"

ca48f461b2dcac2970829e4e0 considered an existing mark expression
plus legacy tags to be an error condition; however these can
be joined by "and" and will in our use case do the right thing.
The github action scripts make use of legacy tags.   We can change
that also but I want to just make sure this combination works
fully as well.

Change-Id: Ifc506de3dd961c01d68d594ec2f5b2c9a0bbad31

1 files changed, 6 insertions, 6 deletions

diff --git a/lib/sqlalchemy/testing/plugin/pytestplugin.py b/lib/sqlalchemy/testing/plugin/pytestplugin.py
index 363a73ecc..6efeac504 100644
--- a/lib/sqlalchemy/testing/plugin/pytestplugin.py
+++ b/lib/sqlalchemy/testing/plugin/pytestplugin.py
@@ -70,16 +70,16 @@ def pytest_addoption(parser):
 
 def pytest_configure(config):
     if plugin_base.exclude_tags or plugin_base.include_tags:
-        if config.option.markexpr:
-            raise ValueError(
-                "Can't combine explicit pytest marks with legacy options "
-                "such as --backend-only, --exclude-tags, etc. "
-            )
-        config.option.markexpr = " and ".join(
+        new_expr = " and ".join(
             list(plugin_base.include_tags)
             + [f"not {tag}" for tag in plugin_base.exclude_tags]
         )
 
+        if config.option.markexpr:
+            config.option.markexpr += f" and {new_expr}"
+        else:
+            config.option.markexpr = new_expr
+
     if config.pluginmanager.hasplugin("xdist"):
         config.pluginmanager.register(XDistHooks())