--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/lldb/test/API/macosx/safe-to-func-call/TestSafeFuncCalls.py	Thu Feb 13 15:10:13 2020 +0900
@@ -0,0 +1,70 @@
+"""Test function call thread safety."""
+
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class TestSafeFuncCalls(TestBase):
+
+    mydir = TestBase.compute_mydir(__file__)
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+        # Find the line numbers that we will step to in main:
+        self.main_source = "main.c"
+
+    @skipUnlessDarwin
+    @add_test_categories(['pyapi'])
+    def test_with_python_api(self):
+        """Test function call thread safety."""
+        self.build()
+        exe = self.getBuildArtifact("a.out")
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+        self.main_source_spec = lldb.SBFileSpec(self.main_source)
+        break1 = target.BreakpointCreateByName("stopper", 'a.out')
+        self.assertTrue(break1, VALID_BREAKPOINT)
+        process = target.LaunchSimple(
+            None, None, self.get_process_working_directory())
+        self.assertTrue(process, PROCESS_IS_VALID)
+        threads = lldbutil.get_threads_stopped_at_breakpoint(process, break1)
+        if len(threads) != 1:
+            self.fail("Failed to stop at breakpoint 1.")
+
+        self.check_number_of_threads(process)
+
+        main_thread = lldb.SBThread()
+        select_thread = lldb.SBThread()
+        for idx in range(0, process.GetNumThreads()):
+            t = process.GetThreadAtIndex(idx)
+            if t.GetName() == "main thread":
+                main_thread = t
+            if t.GetName() == "select thread":
+                select_thread = t
+
+        self.assertTrue(
+            main_thread.IsValid() and select_thread.IsValid(),
+            "Got both expected threads")
+
+        self.safe_to_call_func_on_main_thread(main_thread)
+        self.safe_to_call_func_on_select_thread(select_thread)
+
+    def check_number_of_threads(self, process):
+        self.assertTrue(
+            process.GetNumThreads() == 2,
+            "Check that the process has two threads when sitting at the stopper() breakpoint")
+
+    def safe_to_call_func_on_main_thread(self, main_thread):
+        self.assertTrue(main_thread.SafeToCallFunctions(),
+                        "It is safe to call functions on the main thread")
+
+    def safe_to_call_func_on_select_thread(self, select_thread):
+        self.assertTrue(
+            select_thread.SafeToCallFunctions() == False,
+            "It is not safe to call functions on the select thread")