What's a testing framework?
A testing framework is an execution environment for automated tests. Testing frameworks help teams organize their test suites and in turn help improve the efficiency of testing.
Types of testing frameworks
There are many testing frameworks that work great. Minitest is the default testing framework in Rails 5. However, we will be using the RSpec testing framework instead.
How to set up RSpec in Rails
First, create a new Rails app.
rails new testapp
Then, add rspec-rails to both the :development and :test groups in the Gemfile:
group :development, :test do gem 'rspec-rails', '~> 3.4' end
Download and install by running:
Initialize the spec/ directory (where specs will reside) with:
rails generate rspec:install
This command will add the spec helper, rails helper, and .rspec configuration files.
Use the rspec command to run your specs:
bundle exec rspec
By default, the above code will run all spec files in the spec directory.
To run only a subset of these specs use the following command:
# Run only a specific folder name bundle exec rspec spec/folder_name # Run only specs for a specific type of test such as the post controller bundle exec rspec spec/controllers/post_controller_spec.rb
RSpec.describe Tree do it "is able to age by 1 year increments" do orange_tree = Tree.new orange_tree.age expect(orange_tree.age).to eq(1) end end
The 'describe' and 'it' methods come from rspec-core. The Tree class would be from your code. You can think of 'describe' as a header to describe which class you are testing and 'it' as a string/subheader that states what specifically you are testing in the Tree class. Note: you may or may not need the RSpec in front of the describe depending on your RSpec version.
The last line of the example expresses an expected outcome. If orange_tree.age == 1, then the example passes. If not, it fails with a message like:
expected: #< Tree @age=1 > got: #< Tree @age=0 >
Remember our example in the RSpec Basics section above? The 'to eq' is a matcher! RSpec has many built-in matchers. You can think of them as ways to equate or check certain values or expressions to what you think or expect they would "match" to. In our example, we are saying that we expect orange_tree's age to equal an integer of 1.
Check out the other built-in matchers! https://www.relishapp.com/rspec/rspec-expectations/docs/built-in-matchers
In case you were curious to see how tests are written in minitest. Minitest also allows you to write tests in 'expectation style' which is very similar to how RSpec tests are written.
class TestTree < Minitest::Test def setup @orange_tree = Tree.new @orange_tree.age end def test_age_by_one_year_increments assert_equal 1, @orange_tree.age end end
To run the test enter the following in Terminal/Command Prompt:
Once you run the test this is how the test looks like:
$ ruby tree_test.rb Run options: --seed 30102
. Finished in 0.000980s, 1020.4082 runs/s, 1020.4082 assertions/s. 1 runs, 1 assertions, 0 failures, 0 errors, 0 skips