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|
@allow-old-syntax
Feature: `any_instance`
`any_instance` is the old way to stub or mock any instance of a class but carries the baggage of a global monkey patch on all classes.
Note that we [generally recommend against](../working-with-legacy-code/any-instance) using this feature.
Background:
Given a file named "spec/spec_helper.rb" with:
"""ruby
RSpec.configure do |config|
config.mock_with :rspec do |mocks|
mocks.syntax = :should
end
end
"""
And a file named ".rspec" with:
"""
--require spec_helper
"""
Scenario: Stub a method on any instance of a class
Given a file named "spec/example_spec.rb" with:
"""ruby
RSpec.describe "Stubbing a method with any_instance" do
it "returns the specified value on any instance of the class" do
Object.any_instance.stub(:foo).and_return(:return_value)
o = Object.new
expect(o.foo).to eq(:return_value)
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the examples should all pass
Scenario: Stub multiple methods on any instance of a class
Given a file named "spec/example_spec.rb" with:
"""ruby
RSpec.describe "Stubbing multiple methods with any_instance" do
it "returns the specified values for the given messages" do
Object.any_instance.stub(:foo => 'foo', :bar => 'bar')
o = Object.new
expect(o.foo).to eq('foo')
expect(o.bar).to eq('bar')
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the examples should all pass
Scenario: Stubbing any instance of a class with specific arguments
Given a file named "spec/example_spec.rb" with:
"""ruby
RSpec.describe "Stubbing any instance with arguments" do
it "returns the stubbed value when arguments match" do
Object.any_instance.stub(:foo).with(:param_one, :param_two).and_return(:result_one)
Object.any_instance.stub(:foo).with(:param_three, :param_four).and_return(:result_two)
o = Object.new
expect(o.foo(:param_one, :param_two)).to eq(:result_one)
expect(o.foo(:param_three, :param_four)).to eq(:result_two)
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the examples should all pass
Scenario: Block implementation is passed the receiver as first arg
Given a file named "spec/example_spec.rb" with:
"""ruby
RSpec.describe "Stubbing any instance of a class" do
it 'yields the receiver to the block implementation' do
String.any_instance.stub(:slice) do |value, start, length|
value[start, length]
end
expect('string'.slice(2, 3)).to eq('rin')
end
end
"""
When I run `rspec spec/example_spec.rb`
Then the examples should all pass
Scenario: Expect a message on any instance of a class
Given a file named "spec/example_spec.rb" with:
"""ruby
RSpec.describe "Expecting a message on any instance of a class" do
before do
Object.any_instance.should_receive(:foo)
end
it "passes when an instance receives the message" do
Object.new.foo
end
it "fails when no instance receives the message" do
Object.new.to_s
end
end
"""
When I run `rspec spec/example_spec.rb`
Then it should fail with the following output:
| 2 examples, 1 failure |
| Exactly one instance should have received the following message(s) but didn't: foo |
|
