As a developer, you can test a function independently in developer mode by following the steps given below:
Go to Functions tab in Extension Details page.
All the associated functions will be displayed as a list.
Click on the corresponding function to be tested.
The detailed view page of the function will be displayed, as shown below:
In that page, select Organization from drop-down list and click Add Arguments.
Choose the Argument to be tested from the drop-down list and provide the corresponding value for the chosen argument.
Click Save & Execute.
The confirmation dialog box will pop-up along with the data that is given as input in the arguments field.