Circle area Testing Errorf - float64

[erni93]

About this page, https://github.com/quii/learn-go-with-tests/blob/master/structs-methods-and-interfaces.md

I see a different ways to show the circle area value, in some parts with %f and %.2f

In any case, it won't give you too much info to see why the test fails

Example

With a circle with area 5, I think should be 78.539816339745 (Doing my self or using an online calculator), with got %f want %f it shows

got 78.539816 want 78.539816

But, if I change it to %g

got 78.53981633974483 want 78.539816339745

Ok, perfect, set want to 78.53981633974483

https://golang.org/pkg/fmt/

For floating-point values, width sets the minimum width of the field and precision sets the number of places after the decimal, if appropriate, except that for %g/%G precision sets the maximum number of significant digits (trailing zeros are removed)

Another approach could be round the unit test result, but this can be a bit dangerous

[quii]

This seems like a good improvement - do you want to raise a PR so you get credit for the change?