Re: Re: Asserts using Comparable.compareTo() instead of equals() (for BigDecimal and others)

On Sat, Mar 15, 2014 at 11:35 AM, Miguel Muñoz <[email protected]>wrote:

>
>
> Comrades,
>
>   Okay, I checked out the conversations at
> https://github.com/junit-team/junit/issues/95 and
> https://github.com/junit-team/junit/pull/376, and while I'm not entirely
> convinced that hamcrest is the way to go for comparison assertions, I can
> certainly live with it. So I began searching the JUnit classes for an
> appropriate hamcrest Matcher that would work with BigDecimal values. I
> looked in these packages and classes:
>
> org.junit.matchers.JUnitMatchers
> org.junit.internal.matchers
> org.hamcrest.CoreMatchers
> org.hamcrest
> org.hamcrest.core
> org.hamcrest.internal
>
> I couldn't find any classes that helped me compare two BigDecimal values.
>

I think this was cleared up by the other people on this thread.


> Of course, I could search for a Matcher that doesn’t ship with JUnit, or I
> could write my own Matcher, but a class like BigDecimal, which shipped with
> version 1.0 of the JDK, should be supported by JUnit out of the box. Here’s
> why:
>
> Some of the comments had questions like this:
>
>   What makes you think Comparable assertions are common?
>

I was the one that asked that question. The question was, admittedly, badly
worded, but I also
think you might be taking it out of context.

The thread is here:
https://github.com/junit-team/junit/pull/376#discussion_r418185

In that context, leet3lite was talking about assertions like "isLessThan"
or "isGreaterThanOrEqualTo". I was questioning how often those types of
assertions would be needed.

We couldn't come up with a way to make those kinds of assertions with an
API that was easy to use correctly and hard to use incorrectly without
creating a mini DSL. Since Hamcrest had a DSL that supported it, we decided
not to go forward with changes to JUnit

If we only need assertions that use Comparable to check if two objects are
equal, that would be easier, and perhaps we should do that.


>
>
> I'm going to guess here that the questioner does not work in financial
> services.
>

Actually, I have worked on billing systems in the past, and I'm my current
work includes producing financial reports. In my current project, we do use
BigDecimal, and assertEquals() has met our needs. We just use expected
values that have the same scale as the value we expect. Perhaps that makes
our tests unnecessarily strict and there fragile, but it has worked for us.


Although, given how rarely I used it before I joined this industry, I can
> certainly understand why non-financial developers would think of BigDecimal
> as an obscure class that doesn't get used much. But they're wrong.
>

I don't think anyone on the thread suggested that BigDecimal was obscure.

-- Kevin