diff --git a/libcxx/test/support/test.support/type_algorithms.pass.cpp b/libcxx/test/support/test.support/type_algorithms.pass.cpp
index cf6144d1cb04f..4a76f58f879af 100644
--- a/libcxx/test/support/test.support/type_algorithms.pass.cpp
+++ b/libcxx/test/support/test.support/type_algorithms.pass.cpp
@@ -13,6 +13,12 @@
 #include "test_macros.h"
 #include "type_algorithms.h"
 
+int some_file( void ) {
+
+  return  1+2;     // three!
+
+}
+
 // concatenate
 static_assert(std::is_same<types::concatenate_t<types::type_list<> >, types::type_list<> >::value, "");
 static_assert(std::is_same<types::concatenate_t<types::type_list<int> >, types::type_list<int> >::value, "");
diff --git a/llvm/utils/git/code-format-helper.py b/llvm/utils/git/code-format-helper.py
index c45bb4d935d47..db2d4c5c52273 100644
--- a/llvm/utils/git/code-format-helper.py
+++ b/llvm/utils/git/code-format-helper.py
@@ -148,6 +148,11 @@ def format_run(
             args.end_rev,
             "--",
         ] + cpp_files
+
+        # For manual testing purposes...
+        if "INDUCE_FAILURE_IN_FORMATTER" in " ".join(cpp_files):
+            cf_cmd.insert(1, "--induce-failure")
+
         print(f"Running: {' '.join(cf_cmd)}")
         self.cf_cmd = cf_cmd
         proc = subprocess.run(cf_cmd, capture_output=True)
@@ -192,6 +197,11 @@ def format_run(
             "-r",
             f"{args.start_rev}..{args.end_rev}",
         ] + py_files
+
+        # For manual testing purposes...
+        if "INDUCE_FAILURE_IN_FORMATTER" in " ".join(py_files):
+            darker_cmd += ["--induce-failure"]
+
         print(f"Running: {' '.join(darker_cmd)}")
         self.darker_cmd = darker_cmd
         proc = subprocess.run(darker_cmd, capture_output=True)
diff --git a/llvm/utils/git/test3.cpp b/llvm/utils/git/test3.cpp
new file mode 100644
index 0000000000000..bec7d2853956b
--- /dev/null
+++ b/llvm/utils/git/test3.cpp
@@ -0,0 +1,5 @@
+int three() {
+  if (code) {
+    return 1 + 2;
+  }
+}
\ No newline at end of file
diff --git a/llvm/utils/git/test3.py b/llvm/utils/git/test3.py
new file mode 100644
index 0000000000000..059c5a7f95d10
--- /dev/null
+++ b/llvm/utils/git/test3.py
@@ -0,0 +1,4 @@
+import sys
+
+if __name__ == "__main__":
+    sys.exit(42)