[CQT-289] Avoid creating an Axis (0, 0, 0)

[GuyPuts]

Avoids that an axis of (0, 0, 0) can be created and allows the user to check for this instance before instantiating the class.

[rturrado]

OK, let's have a look at the Axis class globally, and try to refine the logic a bit while not duplicating code.

We have already this function _parse_and_validate_axislike that parses and normalizes:

1. I would divide it into two functions: one for parsing and the other one for normalizing, e.g., parse and normalize (this latter already exists). Can they both be static methods?
2. I would add the check for !(0, 0, 0) to that parse method.

Now, if we go back to the constructor, can we do?

axis_to_parse = axis[0] if axis is a list, otherwise axis
self._value = Axis.parse(axis_to_parse)
self._value = Axis.normalize(self._value)

We can write 3 parametrized tests for each function: constructor, Axis.parse, and Axis.normalize.

Let me know how you see it!

[GuyPuts]

OK, let's have a look at the Axis class globally, and try to refine the logic a bit while not duplicating code.

We have already this function _parse_and_validate_axislike that parses and normalizes:

1. I would divide it into two functions: one for parsing and the other one for normalizing, e.g., parse and normalize (this latter already exists). Can they both be static methods?
2. I would add the check for !(0, 0, 0) to that parse method.

Now, if we go back to the constructor, can we do?

axis_to_parse = axis[0] if axis is a list, otherwise axis
self._value = Axis.parse(axis_to_parse)
self._value = Axis.normalize(self._value)

We can write 3 parametrized tests for each function: constructor, Axis.parse, and Axis.normalize.

Let me know how you see it!

@rturrado if we split the functions, parse "should" return the axis object. Shall we return false if the Axis is invalid?

[rturrado]

@rturrado if we split the functions, parse "should" return the axis object. Shall we return false if the Axis is invalid?

We should raise a ValueError.

[GuyPuts]

@rturrado if we split the functions, parse "should" return the axis object. Shall we return false if the Axis is invalid?

We should raise a ValueError.

I agree that usually a ValueError would be best practice. However, the ticket states that we want to create an Axis without a try/catch block:

So I believe that in this case, maybe it is better to return False?

[rturrado]

No, Guy, let's try to raise the exception. I wrote that ticket. As you can see, I was valuing options, wondering, not stating anything.

[GuyPuts]

No, Guy, let's try to raise the exception. I wrote that ticket. As you can see, I was valuing options, wondering, not stating anything.

Ah alright! I'll raise the exception :)

[rturrado]

Good work, Guy.

I've added a few comments.