It is not very helpful to print that the lengths differ when an
assertion fails, since that does not reveal what the cause of the issue
might be.
Let's print which elements are extra in each list, that should convey
the relevant information to the user. Also use spew to format the
objects, similar to what Equal does, to make the output more readable.
If you were comparing values which when formatted were longer than about 64k then the actual, expected and diff messages were not printed to the console.
`spew`'s default formatter will call `String()` or `Error()` in structs
that implement the `fmt.Stringer` or `error` interfaces. Depending on
the implementation of those, the diff can become quite useless to read
(see the example struct I used for the test case in this commit).
This changes `spew`'s configuration to `DisableMethods` so that it will
always use it's own pretty printer. This makes testing structs less
surprising and generally more useful, without tying the tests to the
implementation of `String()` (the user here can always chose to
`require.Equal(a.String(), b.String())` if testing those is important to
them.
# What
Add `PanicsWithError` that behaves like `PanicsWithValue` but requires
the value to be an `error` and compares an error string against the
error in the same fashion as `EqualError`.
# Why
`PanicsWithValue` is very useful with the value that will panic is a
basic type that can be easily defined in a test, but is less useful for
validating an error because error values may not be easily recreated in
a test to exactly match the error that will be generated in the moment.
This can be because an error will contain fields that aren't exported
and the test may not be able to define the exact error. Most of the time
testing error objects just testing the string is sufficient. This
concept is already supported by this module in the existing `EqualError`
function.
* Added NotSame test for the assert package
* Added NotSame test for the require package
* Included formatted variants of NotSame for both assert and require
Use Go 1.9 t.Helper() to remove testify from the output of the tests and
stop using `\r` to try to overwrite the output.
This means in Go 1.7 and Go 1.8 testify will appear as failing the test.
