Install dependencies in the cloned dir rather than the dir where the tests

are set up from.

Also, make sure that dependencies are cleaned between branch tests since
there are cases when pip doesn't downgrade correctly, which can lead to
tests failing when they shouldn't.

Author: hategan

tests/ci_runner.py

@@ -2,6 +2,7 @@
 import datetime
 import os
 import secrets
+import shutil
 import subprocess
 import sys
 from contextlib import contextmanager
@@ -99,8 +100,14 @@ def install_deps(branch: str, dir: Path) -> None:
     reqpath = dir / 'code' / 'requirements-tests.txt'
     if not reqpath.exists():
         return
+
+    destpath = dir / 'code' / '.packages'
+    # there have been cases when pip failed to leave a consistent
+    # installation after a downgrade, so best to start clean
+    if destpath.exists():
+        shutil.rmtree(str(destpath))
     if MODE == 'plain':
-        run(get_pip(), 'install', '--target', '.packages', '--upgrade', '-r', str(reqpath))
+        run(get_pip(), 'install', '--target', str(destpath), '--upgrade', '-r', str(reqpath))
     else:
         run(get_pip(), 'install', '--upgrade', '-r', str(reqpath))
 
@@ -138,7 +145,7 @@ def run_branch_tests(conf: Dict[str, str], dir: Path, run_id: str, clone: bool =
 
     cwd = (dir / 'code') if clone else Path('.')
     env = dict(os.environ)
-    env['PYTHONPATH'] = str(Path('.').resolve() / '.packages') \
+    env['PYTHONPATH'] = str(cwd.resolve() / '.packages') \
         + ':' + str(cwd.resolve() / 'src') \
         + (':' + env['PYTHONPATH'] if 'PYTHONPATH' in env else '')
     subprocess.run(args, cwd=cwd.resolve(), env=env)