[test] Add script to identify tests that are affected by a change

bin/testing/findtests.py

+#!/usr/bin/env python3
+
+"""
+Find those tests that are affected by changes
+Run this in the build directory
+Warning: This runs 'make clean' on the build directory
+"""
+
+import multiprocessing as mp
+import json
+import subprocess
+from glob import glob
+from subprocess import PIPE
+import os
+
+import sys
+
+# Whether the two lists a and b have a common member
+def has_common_member(myset, mylist):
+    return not myset.isdisjoint(mylist)
+
+def make_dryrun(config):
+    lines = subprocess.check_output(["make", "--dry-run", config["target"]], encoding='ascii').splitlines()
+    return [l for l in lines if "g++" in l]
+
+def build_command_and_dir(config, cache):
+    lines = make_dryrun(config)
+    if len(lines) == 0:
+        with open(cache) as c:
+            data = json.load(c)
+            return data["command"], data["dir"]
+    else:
+        (_, dir), command = [l.split() for l in lines[0].split("&&")]
+        with open(cache, "w") as c:
+            json.dump({"command":command, "dir":dir}, c)
+
+    return command, dir
+
+# find the changes files
+changed_files = subprocess.check_output(["git", "diff-tree", "-r", "--name-only", "HEAD",  "master"], encoding='ascii').splitlines()
+changed_files = set(changed_files)
+
+def is_affected_tests(test):
+    with open(test) as config_file:
+        config = json.load(config_file)
+
+    command, dir = build_command_and_dir(config, "TestTargets/"+config["target"]+".json")
+    # for some reason g++ writes to stderr
+    lines = subprocess.run(command + ["-MM", "-H"], stderr=PIPE, stdout=PIPE, cwd=dir, encoding='ascii').stderr.splitlines()
+
+    # filter lines
+    project_dir = os.path.abspath(os.getcwd().rstrip("build-cmake"))
+    test_files = set([os.path.relpath(l.lstrip(". "), project_dir) for l in lines if project_dir in l])
+
+    if has_common_member(changed_files, test_files):
+        return True, config["name"], config["target"]
+
+    return False, config["name"], config["target"]
+
+if __name__ == '__main__':
+
+    subprocess.run(["make", "clean"])
+    subprocess.run(["make"])
+
+    # create cache folder
+    os.makedirs("TestTargets", exist_ok=True)
+
+    for test in glob("TestMetaData/*json"):
+        print(is_affected_tests(test))