test: do pre-PR A/B-test checkout into temporary directory

Otherwise, they clash with the directories used for the pre-compiled
binaries (as the `build`-subdirectories now no longer contain checked
out repositories, but instead only binaries). Since each pipeline only
uses git_ab_test in precisely one test, loosing the re-use is not a big
deal.

Signed-off-by: Patrick Roy <[email protected]>

Author: roypat

tests/framework/ab_test.py

@@ -24,6 +24,7 @@
 import os
 import statistics
 from pathlib import Path
+from tempfile import TemporaryDirectory
 from typing import Callable, List, Optional, TypeVar
 
 import scipy
@@ -82,19 +83,20 @@ def git_ab_test(
              (alternatively, your comparator can perform any required assertions and not return anything).
     """
 
-    dir_a = git_clone(Path("../build") / a_revision, a_revision)
-    result_a = test_runner(dir_a, True)
+    with TemporaryDirectory() as tmp_dir:
+        dir_a = git_clone(Path(tmp_dir) / a_revision, a_revision)
+        result_a = test_runner(dir_a, True)
 
-    if b_revision:
-        dir_b = git_clone(Path("../build") / b_revision, b_revision)
-    else:
-        # By default, pytest execution happens inside the `tests` subdirectory. Pass the repository root, as
-        # documented.
-        dir_b = Path.cwd().parent
-    result_b = test_runner(dir_b, False)
+        if b_revision:
+            dir_b = git_clone(Path(tmp_dir) / b_revision, b_revision)
+        else:
+            # By default, pytest execution happens inside the `tests` subdirectory. Pass the repository root, as
+            # documented.
+            dir_b = Path.cwd().parent
+        result_b = test_runner(dir_b, False)
 
-    comparison = comparator(result_a, result_b)
-    return result_a, result_b, comparison
+        comparison = comparator(result_a, result_b)
+        return result_a, result_b, comparison
 
 
 DEFAULT_A_DIRECTORY = FC_WORKSPACE_DIR / "build" / "main"
@@ -266,8 +268,6 @@ def git_clone(clone_path, commitish):
         utils.check_output(f"git branch {branch_name} {commitish}")
         _, git_root, _ = utils.run_cmd("git rev-parse --show-toplevel")
         # split off the '\n' at the end of the stdout
-        utils.check_output(
-            f"git clone -b {branch_name} {git_root.strip()} {clone_path}"
-        )
+        utils.check_output(f"git clone -b {branch_name} {git_root.strip()} {clone_path}")
         utils.check_output(f"git branch -D {branch_name}")
     return clone_path