When we install unmanage package in our org, do we need to rerun all the test classes in Salesforce?

Hi Vikas,

Test classes need to pass in the dev org when packaging. Not needed when installing

However, you should design your tests as best you can to pass in customer org. Also if performing call outs, provide a framework that your subscriber can use in their tests to mock responses when your package makes a call out during their tests.

So while they do not have to pass in subscriber org technically, it is still considered a good practice to design your test classes to run in the customer org.