How do you stub methods on a dataset?

[jcavalieri]

I'm using JRuby 9.3.3.0, Sequel 5.53.0, and jdbc-sqlite3 3.28.0.

I'm using mysql for our database which has the method on_duplicate_key_update. This, however, is not available on jdbc-sqlite3 which is used with the unit tests. So I'm trying to stub the method with RSpec. Unfortunately I cannot because the Dataset object is frozen.

ArgumentError:
       Cannot proxy frozen objects, rspec-mocks relies on proxies for method stubbing and expectations.

I tried stubbing the constant TRUE_FREEZE to false. But that didn't work.

How would you go about stubbing a method on a Dataset object?

[jeremyevans]

Instead of trying to modify the frozen dataset, you create a modified copy of it using with_extend:

ds = ds.with_extend{def on_duplicate_key_update(*args) self end}

Alternatively, if you want this method to be available for all of a Database's datasets:

DB.extend_datasets{def on_duplicate_key_update(*args) self end}