Ruby-on-rails – How to organize minitest/unit tests

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After using RSpec for several projects, I'm giving minitest/unit a go. I'm liking it so far, but I miss using describe/context blocks to group my tests/specs in a logical way.

I know minitest/spec provides this functionality, but I like that minitest/unit feels a bit closer to barebones Ruby.

Are there any gems that provide describe/context support for minitest/unit? Or, should I just live with my long, unorganized test files in minitest/unit?

Best Answer

I know several folks coming from RSpec to minitest struggling with the same question. They love the ability to nest using describe/context blocks and want to continue in minitest. There are several solutions:

Use minitest's spec DSL: While there are minor differences, the spec DSL gives you most (all?) of the good parts of the rspec DSL. The big difference is the lack of context blocks. But you can just as easily use describe in its place and everything works as you'd expect.
Use directories and files: I prefer this option. I dislike scrolling through a 300 line test file, regardless whether its using the spec DSL or the classical xUnit style. I do not find nesting unrelated tests helpful. The same rules for comprehension for code applies to tests. So break it up. Create a directory and place several files within it.

Here is an example of how my test files are organized:

test/
     models/
            user/
                 authentication_test.rb
                 email_test.rb
                 reservation_test.rb
                 user_test.rb
                 username_test.rb

I use this structure whether I'm using the spec DSL or the xUnit style. When using the spec DSL I specify what I'm testing in my describe block like so:

require "minitest_helper"

describe User, :authentications do

  before do
    # ...

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.nil? can be used on any object and is true if the object is nil.

.empty? can be used on strings, arrays and hashes and returns true if:

String length == 0
Array length == 0
Hash length == 0

Running .empty? on something that is nil will throw a NoMethodError.

That is where .blank? comes in. It is implemented by Rails and will operate on any object as well as work like .empty? on strings, arrays and hashes.

nil.blank? == true
false.blank? == true
[].blank? == true
{}.blank? == true
"".blank? == true
5.blank? == false
0.blank? == false

.blank? also evaluates true on strings which are non-empty but contain only whitespace:

"  ".blank? == true
"  ".empty? == false

Rails also provides .present?, which returns the negation of .blank?.

Array gotcha: blank? will return false even if all elements of an array are blank. To determine blankness in this case, use all? with blank?, for example:

[ nil, '' ].blank? == false
[ nil, '' ].all? &:blank? == true

Ruby – How to write a switch statement in Ruby

Ruby uses the case expression instead.

case x
when 1..5
  "It's between 1 and 5"
when 6
  "It's 6"
when "foo", "bar"
  "It's either foo or bar"
when String
  "You passed a string"
else
  "You gave me #{x} -- I have no idea what to do with that."
end

Ruby compares the object in the when clause with the object in the case clause using the === operator. For example, 1..5 === x, and not x === 1..5.

This allows for sophisticated when clauses as seen above. Ranges, classes and all sorts of things can be tested for rather than just equality.

Unlike switch statements in many other languages, Ruby’s case does not have fall-through, so there is no need to end each when with a break. You can also specify multiple matches in a single when clause like when "foo", "bar".

Best Answer

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Ruby-on-rails – How to understand nil vs. empty vs. blank in Ruby

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