diff --git a/testing/marionette/error.js b/testing/marionette/error.js
index 66f9f6128810..01a31d498135 100644
--- a/testing/marionette/error.js
+++ b/testing/marionette/error.js
@@ -73,6 +73,17 @@ error.isWebDriverError = function(obj) {
       ("name" in obj && ERRORS.indexOf(obj.name) >= 0);
 };
 
+/**
+ * Wraps an Error prototype in a WebDriverError.  If the given error is
+ * already a WebDriverError, this is effectively a no-op.
+ */
+error.wrap = function(err) {
+  if (error.isWebDriverError(err)) {
+    return err;
+  }
+  return new WebDriverError(`${err.name}: ${err.message}`, err.stack);
+};
+
 /**
  * Unhandled error reporter.  Dumps the error and its stacktrace to console,
  * and reports error to the Browser Console.
@@ -151,11 +162,12 @@ error.fromJson = function(json) {
  * It should not be used directly, as it does not correspond to a real
  * error in the specification.
  */
-this.WebDriverError = function(msg) {
+this.WebDriverError = function(msg, stack = undefined) {
   Error.call(this, msg);
   this.name = "WebDriverError";
   this.message = msg;
   this.status = "webdriver error";
+  this.stack = stack;
 };
 WebDriverError.prototype = Object.create(Error.prototype);
 
diff --git a/testing/marionette/test_error.js b/testing/marionette/test_error.js
index 9b65d6242bf1..c20b93aec51d 100644
--- a/testing/marionette/test_error.js
+++ b/testing/marionette/test_error.js
@@ -64,6 +64,21 @@ add_test(function test_isWebDriverError() {
   run_next_test();
 });
 
+add_test(function test_wrap() {
+  equal(error.wrap(new WebDriverError()).name, "WebDriverError");
+  equal(error.wrap(new InvalidArgumentError()).name, "InvalidArgumentError");
+  equal(error.wrap(new Error()).name, "WebDriverError");
+  equal(error.wrap(new EvalError()).name, "WebDriverError");
+  equal(error.wrap(new InternalError()).name, "WebDriverError");
+  equal(error.wrap(new RangeError()).name, "WebDriverError");
+  equal(error.wrap(new ReferenceError()).name, "WebDriverError");
+  equal(error.wrap(new SyntaxError()).name, "WebDriverError");
+  equal(error.wrap(new TypeError()).name, "WebDriverError");
+  equal(error.wrap(new URIError()).name, "WebDriverError");
+
+  run_next_test();
+});
+
 add_test(function test_stringify() {
   equal("<unprintable error>", error.stringify());
   equal("<unprintable error>", error.stringify("foo"));