Implements equality methods for impf and impfset

[spjuhel]

While working on the Cost Benefit refactoring I need to test the equality between diverse climada objects,
ImpactFuncSet among other. I thought it would be worth to implement the functions as __eq__ methods.

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Changes proposed in this PR:

• Implements an __eq__ methods (==) for ImpactFunc
• Implements an __eq__ methods (==) for ImpactFuncSet

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[peanutfun]

I appreciate the effort, but this looks like boilerplate code to me. If users add new attributes, they will likely miss updating these methods. Wouldn't a simple dataclass decorator do the trick? See https://docs.python.org/3/library/dataclasses.html

[chahank]

What do you mean @peanutfun ? This is the impact function set class and this is about implementing the equality method.

[peanutfun]

@chahank Adding @dataclass will generate this method (and others) automatically for you.

[peanutfun]

I still feel like we do not need to check the actual data inside the ImpactFunc to determine equality. But I am fine with the current approach that ensures lazy evaluation of the data arrays.

I added some suggestions for possible improvement.

Good job with the testing! It's so extensive that I almost feel like it's too much given the amount of "actual" code changes. But I also don't know which tests one could safely drop.

Notice that tests for ImpactFuncSet are still missing.

[peanutfun]

Looking very good! Two tiny nitpicks, then we are done, at least from my perspective 🙂

[peanutfun]

Failing Petals tests are unrelated. Will merge.