add symbol on demand Darwin OSO tests

Author: Tom Yang

lldb/test/API/commands/target/dump-separate-debug-info/oso/TestDumpOso.py

@@ -126,3 +126,33 @@ def test_shows_oso_not_loaded_table_output(self):
                 "0x[a-zA-Z0-9]{16}\s+E\s+.*foo\.o",
             ],
         )
+
+    @skipIfRemote
+    @skipUnlessDarwin
+    def test_osos_loaded_symbols_on_demand(self):
+        self.build(debug_info="dwarf")
+        exe = self.getBuildArtifact("a.out")
+        main_o = self.getBuildArtifact("main.o")
+        foo_o = self.getBuildArtifact("foo.o")
+
+        # Make sure o files exist
+        self.assertTrue(os.path.exists(main_o), f'Make sure "{main_o}" file exists')
+        self.assertTrue(os.path.exists(foo_o), f'Make sure "{foo_o}" file exists')
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, lldbtest.VALID_TARGET)
+
+        self.runCmd("target modules dump separate-debug-info --json")
+
+        # Load symbols on-demand
+        self.runCmd("settings set symbols.load-on-demand true")
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, lldbtest.VALID_TARGET)
+
+        self.runCmd("target modules dump separate-debug-info --json")
+
+        # Check the output
+        osos = self.get_osos_from_json_output()
+        self.assertTrue(osos[exe][main_o]["loaded"])
+        self.assertTrue(osos[exe][foo_o]["loaded"])