RSpec Mock - class does not implement the instance method: jql. Perhaps you meant to use `class_double` instead? - ruby

Question

I want to mock method which use Jira-Ruby gem with jql lib
def call
client = JIRA::Client.new(options)
client.Issue.jql(
"project = #{project_key} AND
status != Done AND
status != Closed AND
status != Cancelled AND
status != Followup",
query_options
)
end
my mock:
let(:jql_options) do
[
"project = TSW-123 AND
status != Done AND
status != Closed AND
status != Cancelled AND
status != Followup",
query_options
]
end
let(:query_options) do
{
start_at: 0,
max_results: 1000
}
end
let(:jira_client) { instance_double(JIRA::Client) }
let(:issue) { instance_double(JIRA::Resource::Issue) }
let(:issue_factory) { instance_double(JIRA::Resource::Issue) }
before do
allow(JIRA::Client).to receive(:new).with(options).and_return(jira_client)
allow(jira_client).to receive(:Issue).and_return(issue_factory)
allow(issue_factory).to receive(:jql).with(*jql_options).and_return(issue)
end
it 'connect to the project' do
expect(subject.call).to eq(project)
end
I'm getting an error:
JIRA::Resource::Issue class does not implement the instance method: jql. Perhaps you meant to use class_double instead?

Answer 1

A few things:
You're using mocking syntax for static values, not objects. My answer to your other question here should help: https://stackoverflow.com/a/60404227/4024628
IMO, the use of instance_double here is fine because you are mocking instances, though if you are going to call the mocked object's methods you often need to define their responses in the instance_double declaration (as mentioned in my linked comment).
Be careful with testing mocked behavior; you should only need to test that the client object is created with certain options, and that jql is called with specific args (meaning, make sure you're validating your code's behavior against breaking changes -- not the gem's behavior).
Your spec is testing that call returns project, but you haven't defined or mocked that anywhere?
You are also defining issue_factory and issue as instance_doubles of the same class, which is inconsistent with the documentation for the classes you're using (typo?).
Something like this might be sufficient:
# You should always name your subject if you are calling methods on it
subject(:instance) { described_class.new }
let(:client) { instance_double(JIRA::Client)
let(:issue_factory) { instance_double(JIRA::Resource::IssueFactory) }
# This likely needs to be an OpenStruct instead since docu says it returns an obj
let(:project) { instance_double(JIRA::Resource::Project) }
before do
allow(client).to receive(:new).with(options) { client }
allow(client).to receive(:Issue) { issue_factory }
allow(issue_factory).to receive(:jql).with(*jql_options) { project }
end
it 'creates client with correct options' do
expect(client).to receive(:new).with(options)
instance.call
end
it 'calls #jql with correct options' do
expect(issue_factory).to receive(:jql).with(*jql_options)
instance.call
end
it { expect(instance.call).to eq(project) }