164 lines
4.4 KiB
Markdown
164 lines
4.4 KiB
Markdown
# Gotchas
|
|
|
|
The purpose of this guide is to document potential "gotchas" that contributors
|
|
might encounter or should avoid during development of GitLab CE and EE.
|
|
|
|
## Do not assert against the absolute value of a sequence-generated attribute
|
|
|
|
Consider the following factory:
|
|
|
|
```ruby
|
|
FactoryBot.define do
|
|
factory :label do
|
|
sequence(:title) { |n| "label#{n}" }
|
|
end
|
|
end
|
|
```
|
|
|
|
Consider the following API spec:
|
|
|
|
```ruby
|
|
require 'rails_helper'
|
|
|
|
describe API::Labels do
|
|
it 'creates a first label' do
|
|
create(:label)
|
|
|
|
get api("/projects/#{project.id}/labels", user)
|
|
|
|
expect(response).to have_http_status(200)
|
|
expect(json_response.first['name']).to eq('label1')
|
|
end
|
|
|
|
it 'creates a second label' do
|
|
create(:label)
|
|
|
|
get api("/projects/#{project.id}/labels", user)
|
|
|
|
expect(response).to have_http_status(200)
|
|
expect(json_response.first['name']).to eq('label1')
|
|
end
|
|
end
|
|
```
|
|
|
|
When run, this spec doesn't do what we might expect:
|
|
|
|
```sh
|
|
1) API::API reproduce sequence issue creates a second label
|
|
Failure/Error: expect(json_response.first['name']).to eq('label1')
|
|
|
|
expected: "label1"
|
|
got: "label2"
|
|
|
|
(compared using ==)
|
|
```
|
|
|
|
That's because FactoryBot sequences are not reseted for each example.
|
|
|
|
Please remember that sequence-generated values exist only to avoid having to
|
|
explicitly set attributes that have a uniqueness constraint when using a factory.
|
|
|
|
### Solution
|
|
|
|
If you assert against a sequence-generated attribute's value, you should set it
|
|
explicitly. Also, the value you set shouldn't match the sequence pattern.
|
|
|
|
For instance, using our `:label` factory, writing `create(:label, title: 'foo')`
|
|
is ok, but `create(:label, title: 'label1')` is not.
|
|
|
|
Following is the fixed API spec:
|
|
|
|
```ruby
|
|
require 'rails_helper'
|
|
|
|
describe API::Labels do
|
|
it 'creates a first label' do
|
|
create(:label, title: 'foo')
|
|
|
|
get api("/projects/#{project.id}/labels", user)
|
|
|
|
expect(response).to have_http_status(200)
|
|
expect(json_response.first['name']).to eq('foo')
|
|
end
|
|
|
|
it 'creates a second label' do
|
|
create(:label, title: 'bar')
|
|
|
|
get api("/projects/#{project.id}/labels", user)
|
|
|
|
expect(response).to have_http_status(200)
|
|
expect(json_response.first['name']).to eq('bar')
|
|
end
|
|
end
|
|
```
|
|
|
|
## Avoid using `expect_any_instance_of` or `allow_any_instance_of` in RSpec
|
|
|
|
### Why
|
|
|
|
* Because it is not isolated therefore it might be broken at times.
|
|
* Because it doesn't work whenever the method we want to stub was defined
|
|
in a prepended module, which is very likely the case in EE. We could see
|
|
error like this:
|
|
|
|
```
|
|
1.1) Failure/Error: expect_any_instance_of(ApplicationSetting).to receive_messages(messages)
|
|
Using `any_instance` to stub a method (elasticsearch_indexing) that has been defined on a prepended module (EE::ApplicationSetting) is not supported.
|
|
```
|
|
|
|
### Alternative: `expect_next_instance_of`
|
|
|
|
Instead of writing:
|
|
|
|
```ruby
|
|
# Don't do this:
|
|
expect_any_instance_of(Project).to receive(:add_import_job)
|
|
```
|
|
|
|
We could write:
|
|
|
|
```ruby
|
|
# Do this:
|
|
expect_next_instance_of(Project) do |project|
|
|
expect(project).to receive(:add_import_job)
|
|
end
|
|
```
|
|
|
|
If we also want to expect the instance was initialized with some particular
|
|
arguments, we could also pass it to `expect_next_instance_of` like:
|
|
|
|
```ruby
|
|
# Do this:
|
|
expect_next_instance_of(MergeRequests::RefreshService, project, user) do |refresh_service|
|
|
expect(refresh_service).to receive(:execute).with(oldrev, newrev, ref)
|
|
end
|
|
```
|
|
|
|
This would expect the following:
|
|
|
|
```ruby
|
|
# Above expects:
|
|
refresh_service = MergeRequests::RefreshService.new(project, user)
|
|
refresh_service.execute(oldrev, newrev, ref)
|
|
```
|
|
|
|
## Do not `rescue Exception`
|
|
|
|
See ["Why is it bad style to `rescue Exception => e` in Ruby?"][Exception].
|
|
|
|
_**Note:** This rule is [enforced automatically by
|
|
Rubocop](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-4-stable/.rubocop.yml#L911-914)._
|
|
|
|
[Exception]: http://stackoverflow.com/q/10048173/223897
|
|
|
|
## Do not use inline JavaScript in views
|
|
|
|
Using the inline `:javascript` Haml filters comes with a
|
|
performance overhead. Using inline JavaScript is not a good way to structure your code and should be avoided.
|
|
|
|
_**Note:** We've [removed these two filters](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/config/initializers/hamlit.rb)
|
|
in an initializer._
|
|
|
|
### Further reading
|
|
|
|
- Stack Overflow: [Why you should not write inline JavaScript](http://programmers.stackexchange.com/questions/86589/why-should-i-avoid-inline-scripting)
|