diff --git a/testing/BUILD.gn b/testing/BUILD.gn
index 9a01845..97ea865 100644
--- a/testing/BUILD.gn
+++ b/testing/BUILD.gn
@@ -7,6 +7,8 @@
 source_set("test_support") {
   testonly = true
   sources = [
+    "command_line_helpers.cpp",
+    "command_line_helpers.h",
     "font_renamer.cpp",
     "font_renamer.h",
     "fx_string_testhelpers.cpp",
diff --git a/testing/command_line_helpers.cpp b/testing/command_line_helpers.cpp
new file mode 100644
index 0000000..758f278
--- /dev/null
+++ b/testing/command_line_helpers.cpp
@@ -0,0 +1,23 @@
+// Copyright 2022 The PDFium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "testing/command_line_helpers.h"
+
+bool ParseSwitchKeyValue(const std::string& arg,
+                         const std::string& key,
+                         std::string* value) {
+  if (arg.size() <= key.size() || arg.compare(0, key.size(), key) != 0)
+    return false;
+
+  *value = arg.substr(key.size());
+  return true;
+}
+
+FPDF_RENDERER_TYPE GetDefaultRendererType() {
+#if defined(_SKIA_SUPPORT_)
+  return FPDF_RENDERERTYPE_SKIA;
+#else
+  return FPDF_RENDERERTYPE_AGG;
+#endif
+}
diff --git a/testing/command_line_helpers.h b/testing/command_line_helpers.h
new file mode 100644
index 0000000..cc134cb
--- /dev/null
+++ b/testing/command_line_helpers.h
@@ -0,0 +1,23 @@
+// Copyright 2022 The PDFium Authors
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TESTING_COMMAND_LINE_HELPERS_H_
+#define TESTING_COMMAND_LINE_HELPERS_H_
+
+#include <string>
+
+#include "public/fpdfview.h"
+
+// Extract the value from a keyed command line argument.
+// `arg` is expected to be "--key=value", and `key` is "--key=".
+bool ParseSwitchKeyValue(const std::string& arg,
+                         const std::string& key,
+                         std::string* value);
+
+// Identifies the compile-time default 2D graphics library to use for rendering
+// to FPDF_BITMAPs. Used as part of support to override the renderer at runtime
+// based upon command line options.
+FPDF_RENDERER_TYPE GetDefaultRendererType();
+
+#endif  // TESTING_COMMAND_LINE_HELPERS_H_