Index: lldb/test/API/tools/lldb-server/TestGdbRemotePlatformFile.py
===================================================================
--- lldb/test/API/tools/lldb-server/TestGdbRemotePlatformFile.py
+++ lldb/test/API/tools/lldb-server/TestGdbRemotePlatformFile.py
@@ -100,6 +100,80 @@
                 True)
             self.expect_gdbremote_sequence()
 
+    @skipIfWindows
+    @add_test_categories(["llgs"])
+    def test_platform_file_size(self):
+        server = self.connect_to_debug_monitor()
+        self.assertIsNotNone(server)
+
+        with tempfile.NamedTemporaryFile() as temp_file:
+            test_data = b"test data of some length"
+            temp_file.write(test_data)
+            temp_file.flush()
+
+            self.do_handshake()
+            self.test_sequence.add_log_lines(
+                ["read packet: $vFile:size:%s#00" % (
+                    binascii.b2a_hex(temp_file.name.encode()).decode(),),
+                 {"direction": "send",
+                 "regex": r"^\$F([0-9a-fA-F]+)+#[0-9a-fA-F]{2}$",
+                 "capture": {1: "size"}}],
+                True)
+            context = self.expect_gdbremote_sequence()
+            self.assertEqual(int(context["size"], 16), len(test_data))
+
+    @skipIfWindows
+    @add_test_categories(["llgs"])
+    def test_platform_file_mode(self):
+        server = self.connect_to_debug_monitor()
+        self.assertIsNotNone(server)
+
+        with tempfile.NamedTemporaryFile() as temp_file:
+            test_mode = 0o751
+            os.chmod(temp_file.fileno(), test_mode)
+
+            self.do_handshake()
+            self.test_sequence.add_log_lines(
+                ["read packet: $vFile:mode:%s#00" % (
+                    binascii.b2a_hex(temp_file.name.encode()).decode(),),
+                 {"direction": "send",
+                 "regex": r"^\$F([0-9a-fA-F]+)+#[0-9a-fA-F]{2}$",
+                 "capture": {1: "mode"}}],
+                True)
+            context = self.expect_gdbremote_sequence()
+            self.assertEqual(int(context["mode"], 16), test_mode)
+
+    @skipIfWindows
+    @add_test_categories(["llgs"])
+    def test_platform_file_exists(self):
+        server = self.connect_to_debug_monitor()
+        self.assertIsNotNone(server)
+
+        with tempfile.NamedTemporaryFile() as temp_file:
+            self.do_handshake()
+            self.test_sequence.add_log_lines(
+                ["read packet: $vFile:exists:%s#00" % (
+                    binascii.b2a_hex(temp_file.name.encode()).decode(),),
+                 "send packet: $F,1#00"],
+                True)
+            self.expect_gdbremote_sequence()
+
+    @skipIfWindows
+    @add_test_categories(["llgs"])
+    def test_platform_file_exists_not(self):
+        server = self.connect_to_debug_monitor()
+        self.assertIsNotNone(server)
+
+        with tempfile.TemporaryDirectory() as temp_dir:
+            test_path = os.path.join(temp_dir, "nonexist")
+            self.do_handshake()
+            self.test_sequence.add_log_lines(
+                ["read packet: $vFile:exists:%s#00" % (
+                    binascii.b2a_hex(test_path.encode()).decode(),),
+                 "send packet: $F,0#00"],
+                True)
+            self.expect_gdbremote_sequence()
+
     def expect_error(self):
         self.test_sequence.add_log_lines(
             [{"direction": "send",