diff --git a/test/functional/test_framework/test_framework.py b/test/functional/test_framework/test_framework.py
--- a/test/functional/test_framework/test_framework.py
+++ b/test/functional/test_framework/test_framework.py
@@ -112,8 +112,9 @@
 
         PortSeed.n = self.options.port_seed
 
-        os.environ['PATH'] = self.options.srcdir + ":" + \
-            self.options.srcdir + "/qt:" + os.environ['PATH']
+        os.environ['PATH'] = self.options.srcdir + os.pathsep + \
+            self.options.srcdir + os.path.sep + "qt" + os.pathsep + \
+            os.environ['PATH']
 
         check_json_precision()
 
@@ -173,11 +174,12 @@
                 "Note: bitcoinds were not stopped and may still be running")
 
         if not self.options.nocleanup and not self.options.noshutdown and success != TestStatus.FAILED:
-            self.log.info("Cleaning up")
-            shutil.rmtree(self.options.tmpdir)
+            self.log.info("Cleaning up {} on exit".format(self.options.tmpdir))
+            cleanup_tree_on_exit = True
         else:
             self.log.warning(
                 "Not cleaning up dir {}".format(self.options.tmpdir))
+            cleanup_tree_on_exit = False
 
         if success == TestStatus.PASSED:
             self.log.info("Tests successful")
@@ -192,6 +194,8 @@
                 os.path.dirname(os.path.realpath(__file__)) + "/../combine_logs.py"), self.options.tmpdir))
             exit_code = TEST_EXIT_FAILED
         logging.shutdown()
+        if cleanup_tree_on_exit:
+            shutil.rmtree(self.options.tmpdir)
         sys.exit(exit_code)
 
     # Methods to override in subclass test scripts.
diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -110,7 +110,7 @@
         tmpdir_arg = ["--tmpdir={}".format(testdir)]
         name = t
         time0 = time.time()
-        process = subprocess.Popen([os.path.join(self.tests_dir, test_argv[0])] + test_argv[1:] + self.flags + portseed_arg + tmpdir_arg,
+        process = subprocess.Popen([sys.executable, os.path.join(self.tests_dir, test_argv[0])] + test_argv[1:] + self.flags + portseed_arg + tmpdir_arg,
                                    universal_newlines=True,
                                    stdout=log_stdout,
                                    stderr=log_stderr)
@@ -290,7 +290,7 @@
         # and exit.
         parser.print_help()
         subprocess.check_call(
-            [os.path.join(tests_dir, test_list[0]), '-h'])
+            [sys.executable, os.path.join(tests_dir, test_list[0]), '-h'])
         sys.exit(0)
 
     if not args.keepcache:
@@ -331,8 +331,8 @@
     if len(test_list) > 1 and num_jobs > 1:
         # Populate cache
         try:
-            subprocess.check_output(
-                [os.path.join(tests_dir, 'create_cache.py')] + flags + [os.path.join("--tmpdir={}", "cache") .format(tmpdir)])
+            subprocess.check_output([sys.executable, os.path.join(
+                tests_dir, 'create_cache.py')] + flags + [os.path.join("--tmpdir={}", "cache") .format(tmpdir)])
         except subprocess.CalledProcessError as e:
             sys.stdout.buffer.write(e.output)
             raise
@@ -514,7 +514,7 @@
             print('\n============')
             print('{}Combined log for {}:{}'.format(BOLD[1], testdir, BOLD[0]))
             print('============\n')
-            combined_logs, _ = subprocess.Popen([os.path.join(
+            combined_logs, _ = subprocess.Popen([sys.executable, os.path.join(
                 tests_dir, 'combine_logs.py'), '-c', testdir], universal_newlines=True, stdout=subprocess.PIPE).communicate()
             print("\n".join(deque(combined_logs.splitlines(), combined_logs_len)))
 
diff --git a/test/util/bitcoin-util-test.py b/test/util/bitcoin-util-test.py
--- a/test/util/bitcoin-util-test.py
+++ b/test/util/bitcoin-util-test.py
@@ -38,8 +38,8 @@
     # Add the format/level to the logger
     logging.basicConfig(format=formatter, level=level)
 
-    bctester(config["environment"]["SRCDIR"] + "/test/util/data",
-             "bitcoin-util-test.json", config["environment"])
+    bctester(os.path.join(config["environment"]["SRCDIR"], "test",
+                          "util", "data"), "bitcoin-util-test.json", config["environment"])
 
 
 def bctester(testDir, input_basename, buildenv):