diff --git a/backends.py b/backends.py
index aa79c7d48..054130e77 100644
--- a/backends.py
+++ b/backends.py
@@ -94,6 +94,14 @@ def do_conf_file(src, dst, confdata):
         pass
     os.replace(dst_tmp, dst)
 
+class TestSerialisation:
+    def __init__(self, name, fname, is_cross, exe_wrapper, is_parallel):
+        self.name = name
+        self.fname = fname
+        self.is_cross = is_cross
+        self.exe_runner = exe_wrapper
+        self.is_parallel = is_parallel
+
 # It may seem a bit silly that this Backend class exists on its own
 # rather than being a part of NinjaBackend, which is the only class
 # that uses Backend. The point is that common functionality
@@ -483,14 +491,14 @@ class NinjaBackend(Backend):
     def write_test_file(self, datafile):
         arr = []
         for t in self.build.get_tests():
-            name = t.get_name()
             fname = os.path.join(self.environment.get_build_dir(), self.get_target_filename(t.get_exe()))
             is_cross = self.environment.is_cross_build()
             if is_cross:
                 exe_wrapper = self.environment.cross_info.get('exe_wrapper', None)
             else:
                 exe_wrapper = None
-            arr.append([name, fname, is_cross, exe_wrapper])
+            ts = TestSerialisation(t.get_name(), fname, is_cross, exe_wrapper, t.is_parallel)
+            arr.append(ts)
         pickle.dump(arr, datafile)
 
     def generate_dep_gen_rules(self, outfile):
diff --git a/interpreter.py b/interpreter.py
index dcf733928..917caf035 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -642,10 +642,11 @@ class SharedLibrary(BuildTarget):
         return aliases
 
 class Test(InterpreterObject):
-    def __init__(self, name, exe):
+    def __init__(self, name, exe, is_parallel):
         InterpreterObject.__init__(self)
         self.name = name
         self.exe = exe
+        self.is_parallel = is_parallel
         
     def get_exe(self):
         return self.exe
@@ -1121,7 +1122,10 @@ class Interpreter():
 
     def func_test(self, node, args, kwargs):
         self.validate_arguments(args, 2, [str, Executable])
-        t = Test(args[0], args[1])
+        par = kwargs.get('is_parallel', True)
+        if not isinstance(par, bool):
+            raise InterpreterException('Keyword argument is_parallel must be a boolean.')
+        t = Test(args[0], args[1], par)
         self.build.tests.append(t)
         mlog.debug('Adding test "', mlog.bold(args[0]), '".', sep='')
 
diff --git a/meson_test.py b/meson_test.py
index 1ae41940f..750c29805 100755
--- a/meson_test.py
+++ b/meson_test.py
@@ -100,24 +100,21 @@ def run_tests(options, datafilename):
             num_workers = int(os.environ[varname])
         except ValueError:
             write_log('Invalid value in %s, using 1 thread.' % varname)
+            num_workers = 1
     else:
         num_workers = multiprocessing.cpu_count()
     executor = conc.ThreadPoolExecutor(max_workers=num_workers)
     futures = []
     for i, test in enumerate(tests):
-        name = test[0]
-        fname = test[1]
-        is_cross = test[2]
-        exe_runner = test[3]
-        is_parallel = False
-        if not is_parallel:
+        if not test.is_parallel:
             drain_futures(futures)
             futures = []
-            f = run_single_test(wrap, fname, is_cross, exe_runner)
-            print_stats(numlen, tests, name, f, i, logfile)
+            res = run_single_test(wrap, test.fname, test.is_cross, test.exe_runner)
+            print_stats(numlen, tests, test.name, res, i, logfile)
         else:
-            f = executor.submit(run_single_test, wrap, fname, is_cross, exe_runner)
-            futures.append((f, numlen, tests, name, f, i, logfile))
+            f = executor.submit(run_single_test, wrap, test.fname,
+                                test.is_cross, test.exe_runner)
+            futures.append((f, numlen, tests, test.name, f, i, logfile))
     drain_futures(futures)
     print('\nFull log written to %s.' % logfilename)