I need to write a test class for trigger on a standard object. opportunity.
The plan is package the trigger and test class as a free app so users can re-use the component.
As we all know the test coverages are environment dependent. They are dependent on factors like
(1) Custom Mandatory fields, (2) Custom Validation rules & (3) other custom triggers on the object
Are these best practices around creating test class for standard object which can have a good coverage irrespective of the test environment ?