How to set both onInstall and seeAllData to true for a test method

Question

I tried to set SeeAllData = true for the test method with OnInstall = true. But I was not able to save the test class if I use "@isTest(OnInstall=true,SeeAllData=true)", so I saved it with "@isTest(OnInstall=true)". The package installation failed in our client's org because I'm inserting Account, Contact, and Product records in my test method and their Contact trigger is throwing the error "System.QueryException: List has no rows for assignment to SObject" (the insert statement in my test method is firing our client's trigger and they are using a query in their trigger to retrieve an existing record with a specific value in Name field "[SELECT Id from Account WHERE Name = 'XXX' limit 1]"). If I can set SeeAllData = true, then my test method will not fail, so please help me with this. Thanks in advance.

Answer 1

Don't use a comma for the attributes:

@isTest(SeeAllData=true OnInstall=true)

As far as I can tell, this isn't documented anywhere.