diff --git a/lib/unexpected-sinon.js b/lib/unexpected-sinon.js
index <HASH>..<HASH> 100644
--- a/lib/unexpected-sinon.js
+++ b/lib/unexpected-sinon.js
@@ -326,7 +326,10 @@
                 var originalValues = spies.map(function (spy) {
                     var originalValue = {};
                     for (var propertyName in spy) {
-                        if (spy.hasOwnProperty(propertyName) && typeof spy[propertyName] !== 'function') {
+                        if (propertyName === 'func') {
+                            originalValue.func = spy.func;
+                            spy.func = function () {};
+                        } else if (spy.hasOwnProperty(propertyName) && typeof spy[propertyName] !== 'function') {
                             if (Array.isArray(spy[propertyName])) {
                                 originalValue[propertyName] = [].concat(spy[propertyName]);
                             } else {
Make ... to have calls satisfying <function> work for spies that have side effects.

Won't work unless <URL>