To add a collaborator to this project you will need to use the Relish gem to add the collaborator via a terminal command. Soon you'll be able to also add collaborators here!
More about adding a collaborator`respond_to` matcher
Use the respond_to matcher to specify details of an object's interface. In its most basic form:
expect(obj).to respond_to(:foo) # pass if obj.respond_to?(:foo)
You can specify that an object responds to multiple messages in a single statement with
multiple arguments passed to the matcher:
expect(obj).to respond_to(:foo, :bar) # passes if obj.respond_to?(:foo) && obj.respond_to?(:bar)
If the number of arguments accepted by the method is important to you, you can specify
that as well:
expect(obj).to respond_to(:foo).with(1).argument
expect(obj).to respond_to(:bar).with(2).arguments
Note that this matcher relies entirely upon #respond_to?. If an object dynamically responds
to a message via #method_missing, but does not indicate this via #respond_to?, then this
matcher will give you false results.
- Scenarios
-
- basic usage
-
- Given
-
a file named "respond_to_matcher_spec.rb" with:
RSpec.describe "a string" do it { is_expected.to respond_to(:length) } it { is_expected.to respond_to(:hash, :class, :to_s) } it { is_expected.not_to respond_to(:to_model) } it { is_expected.not_to respond_to(:compact, :flatten) } # deliberate failures it { is_expected.to respond_to(:to_model) } it { is_expected.to respond_to(:compact, :flatten) } it { is_expected.not_to respond_to(:length) } it { is_expected.not_to respond_to(:hash, :class, :to_s) } # mixed examples--String responds to :length but not :flatten # both specs should fail it { is_expected.to respond_to(:length, :flatten) } it { is_expected.not_to respond_to(:length, :flatten) } end
- When
-
I run
rspec respond_to_matcher_spec.rb
- Then
-
the output should contain all of these:
10 examples, 6 failures expected "a string" to respond to :to_model expected "a string" to respond to :compact, :flatten expected "a string" not to respond to :length expected "a string" not to respond to :hash, :class, :to_s expected "a string" to respond to :flatten expected "a string" not to respond to :length
- specify arguments
-
- Given
-
a file named "respond_to_matcher_argument_checking_spec.rb" with:
RSpec.describe 7 do it { is_expected.to respond_to(:zero?).with(0).arguments } it { is_expected.not_to respond_to(:zero?).with(1).argument } it { is_expected.to respond_to(:between?).with(2).arguments } it { is_expected.not_to respond_to(:between?).with(7).arguments } # deliberate failures it { is_expected.to respond_to(:zero?).with(1).argument } it { is_expected.not_to respond_to(:zero?).with(0).arguments } it { is_expected.to respond_to(:between?).with(7).arguments } it { is_expected.not_to respond_to(:between?).with(2).arguments } end
- When
-
I run
rspec respond_to_matcher_argument_checking_spec.rb
- Then
-
the output should contain all of these:
8 examples, 4 failures expected 7 to respond to :zero? with 1 argument expected 7 not to respond to :zero? with 0 arguments expected 7 to respond to :between? with 7 arguments expected 7 not to respond to :between? with 2 arguments
Last published over 7 years ago by myronmarston.