Make sure new venvs use the latest pip, etc. (#161)

Author: ericsnowcurrently

pyperformance/run.py

@@ -65,6 +65,7 @@ def run_benchmarks(should_run, python, options):
         common = VenvForBenchmarks.ensure(
             _venv.get_venv_root(runid.name, python=info),
             info,
+            upgrade='oncreate',
             inherit_environ=options.inherit_environ,
         )
 
@@ -92,6 +93,7 @@ def run_benchmarks(should_run, python, options):
         venv = VenvForBenchmarks.ensure(
             venv_root,
             info,
+            upgrade='oncreate',
             inherit_environ=options.inherit_environ,
         )
         try:

pyperformance/venv.py

@@ -150,7 +150,15 @@ def ensure(cls, root, python=None, *,
                upgrade=False,
                **kwargs
                ):
-        if _venv.venv_exists(root):
+        exists = _venv.venv_exists(root)
+        if upgrade == 'oncreate':
+            upgrade = not exists
+        elif upgrade == 'onexists':
+            upgrade = exists
+        elif isinstance(upgrade, str):
+            raise NotImplementedError(upgrade)
+
+        if exists:
             self = super().ensure(root)
             if upgrade:
                 self.upgrade_pip()