added unit testing, and started implementing unit tests...phew

node_modules/@sinonjs/commons/lib/function-name.js

@@ -0,0 +1,17 @@
+"use strict";
+
+module.exports = function functionName(func) {
+    if (!func) {
+        return "";
+    }
+
+    return (
+        func.displayName ||
+        func.name ||
+        // Use function decomposition as a last resort to get function
+        // name. Does not rely on function decomposition to work - if it
+        // doesn't debugging will be slightly less informative
+        // (i.e. toString will say 'spy' rather than 'myFunc').
+        (String(func).match(/function ([^\s(]+)/) || [])[1]
+    );
+};