fixup! move test for invalid invariant index into separate test

Author: Michael137

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/invalid-variant/Makefile

@@ -0,0 +1,5 @@
+CXX_SOURCES := main.cpp
+CXXFLAGS_EXTRAS := -std=c++17
+USE_LIBSTDCPP := 1
+
+include Makefile.rules

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/invalid-variant/TestDataFormatterInvalidStdVariant.py

@@ -0,0 +1,29 @@
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class InvalidStdVariantDataFormatterTestCase(TestBase):
+    @add_test_categories(["libstdcxx"])
+    def do_test(self):
+        """Test STL data formatters for std::variant with invalid index."""
+
+        (_, _, thread, _) = lldbutil.run_to_source_breakpoint(
+            self, "// break here", lldb.SBFileSpec("main.cpp", False)
+        )
+
+        self.expect(
+            "frame variable v1",
+            substrs=["v1 =  Active Type = char  {", "Value = 'x'", "}"],
+        )
+
+        var_v1 = thread.frames[0].FindVariable("v1")
+        var_v1_raw_obj = var_v1.GetNonSyntheticValue()
+        index_obj = var_v1_raw_obj.GetChildMemberWithName("_M_index")
+        self.assertTrue(index_obj and index_obj.IsValid())
+
+        INVALID_INDEX = "100"
+        index_obj.SetValueFromCString(INVALID_INDEX)
+
+        self.expect("frame variable v1", substrs=["v1 =  <Invalid>"])

lldb/test/API/functionalities/data-formatter/data-formatter-stl/libstdcpp/invalid-variant/main.cpp

@@ -0,0 +1,11 @@
+#include <cstdio>
+#include <variant>
+
+int main() {
+  std::variant<int, double, char> v1;
+  v1 = 'x';
+
+  std::puts("// break here");
+
+  return 0;
+}