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|
Feature: `respond_to` matcher
Use the `respond_to` matcher to specify details of an object's interface. In its most basic form:
```ruby
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:
```ruby
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:
```ruby
expect(obj).to respond_to(:foo).with(1).argument
expect(obj).to respond_to(:bar).with(2).arguments
expect(obj).to respond_to(:baz).with(1..2).arguments
expect(obj).to respond_to(:xyz).with_unlimited_arguments
```
If your Ruby version supports keyword arguments, you can specify a list of keywords accepted
by the method.
```ruby
expect(obj).to respond_to(:foo).with_keywords(:ichi, :ni)
expect(obj).to respond_to(:bar).with(2).arguments.and_keywords(:san, :yon)
expect(obj).to respond_to(:baz).with_arbitrary_keywords
```
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.
Scenario: Basic usage
Given a file named "respond_to_matcher_spec.rb" with:
"""ruby
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 |
Scenario: Specify arguments
Given a file named "respond_to_matcher_argument_checking_spec.rb" with:
"""ruby
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 |
@skip-when-splat-args-unsupported
Scenario: Specify arguments range
Given a file named "respond_to_matcher_argument_range_checking_spec.rb" with:
"""ruby
class MyClass
def build(name, options = {})
end
def inspect
'my_object'
end
end
RSpec.describe MyClass do
it { is_expected.to respond_to(:build).with(1..2).arguments }
it { is_expected.not_to respond_to(:build).with(0..1).arguments }
it { is_expected.not_to respond_to(:build).with(2..3).arguments }
it { is_expected.not_to respond_to(:build).with(0..3).arguments }
# deliberate failures
it { is_expected.not_to respond_to(:build).with(1..2).arguments }
it { is_expected.to respond_to(:build).with(0..1).arguments }
it { is_expected.to respond_to(:build).with(2..3).arguments }
it { is_expected.to respond_to(:build).with(0..3).arguments }
end
"""
When I run `rspec respond_to_matcher_argument_range_checking_spec.rb`
Then the output should contain all of these:
| 8 examples, 4 failures |
| expected my_object not to respond to :build with 1..2 arguments |
| expected my_object to respond to :build with 0..1 arguments |
| expected my_object to respond to :build with 2..3 arguments |
| expected my_object to respond to :build with 0..3 arguments |
@skip-when-splat-args-unsupported
Scenario: Specify unlimited arguments
Given a file named "respond_to_matcher_unlimited_argument_checking_spec.rb" with:
"""ruby
class MyClass
def greet(message = 'Hello', *people)
end
def hail(person)
end
def inspect
'my_object'
end
end
RSpec.describe MyClass do
it { is_expected.to respond_to(:greet).with_unlimited_arguments }
it { is_expected.to respond_to(:greet).with(1).argument.and_unlimited_arguments }
it { is_expected.not_to respond_to(:hail).with_unlimited_arguments }
it { is_expected.not_to respond_to(:hail).with(1).argument.and_unlimited_arguments }
# deliberate failures
it { is_expected.not_to respond_to(:greet).with_unlimited_arguments }
it { is_expected.not_to respond_to(:greet).with(1).argument.and_unlimited_arguments }
it { is_expected.to respond_to(:hail).with_unlimited_arguments }
it { is_expected.to respond_to(:hail).with(1).argument.and_unlimited_arguments }
end
"""
When I run `rspec respond_to_matcher_unlimited_argument_checking_spec.rb`
Then the output should contain all of these:
| 8 examples, 4 failures |
| expected my_object not to respond to :greet with unlimited arguments |
| expected my_object not to respond to :greet with 1 argument and unlimited arguments |
| expected my_object to respond to :hail with unlimited arguments |
| expected my_object to respond to :hail with 1 argument and unlimited arguments |
@skip-when-keyword-args-unsupported
Scenario: Specify keywords
Given a file named "respond_to_matcher_keyword_checking_spec.rb" with:
"""ruby
class MyClass
def find(name = 'id', limit: 1_000, offset: 0)
[]
end
def inspect
'my_object'
end
end
RSpec.describe MyClass do
it { is_expected.to respond_to(:find).with_keywords(:limit, :offset) }
it { is_expected.to respond_to(:find).with(1).argument.and_keywords(:limit, :offset) }
it { is_expected.not_to respond_to(:find).with_keywords(:limit, :offset, :page) }
it { is_expected.not_to respond_to(:find).with(1).argument.and_keywords(:limit, :offset, :page) }
# deliberate failures
it { is_expected.to respond_to(:find).with_keywords(:limit, :offset, :page) }
it { is_expected.to respond_to(:find).with(1).argument.and_keywords(:limit, :offset, :page) }
it { is_expected.not_to respond_to(:find).with_keywords(:limit, :offset) }
it { is_expected.not_to respond_to(:find).with(1).argument.and_keywords(:limit, :offset) }
end
"""
When I run `rspec respond_to_matcher_keyword_checking_spec.rb`
Then the output should contain all of these:
| 8 examples, 4 failures |
| expected my_object to respond to :find with keywords :limit, :offset, and :page |
| expected my_object to respond to :find with 1 argument and keywords :limit, :offset, and :page |
| expected my_object not to respond to :find with keywords :limit and :offset |
| expected my_object not to respond to :find with 1 argument and keywords :limit and :offset |
@skip-when-keyword-args-unsupported
Scenario: Specify any keywords
Given a file named "respond_to_matcher_any_keywords_checking_spec.rb" with:
"""ruby
class MyClass
def build(name: 'object', **opts)
end
def create(name: 'object', type: String)
end
def inspect
'my_object'
end
end
RSpec.describe MyClass do
it { is_expected.to respond_to(:build).with_any_keywords }
it { is_expected.to respond_to(:build).with_keywords(:name).and_any_keywords }
it { is_expected.not_to respond_to(:create).with_any_keywords }
it { is_expected.not_to respond_to(:create).with_keywords(:name).and_any_keywords }
# deliberate failures
it { is_expected.not_to respond_to(:build).with_any_keywords }
it { is_expected.not_to respond_to(:build).with_keywords(:name).and_any_keywords }
it { is_expected.to respond_to(:create).with_any_keywords }
it { is_expected.to respond_to(:create).with_keywords(:name).and_any_keywords }
end
"""
When I run `rspec respond_to_matcher_any_keywords_checking_spec.rb`
Then the output should contain all of these:
| 8 examples, 4 failures |
| expected my_object not to respond to :build with any keywords |
| expected my_object not to respond to :build with keyword :name and any keywords |
| expected my_object to respond to :create with any keywords |
| expected my_object to respond to :create with keyword :name and any keywords |
@skip-when-required-keyword-args-unsupported
Scenario: Specify required keywords
Given a file named "respond_to_matcher_required_keyword_checking_spec.rb" with:
"""ruby
class MyClass
def plant(seed:, fertilizer: nil, water: 'daily')
[]
end
def inspect
'my_object'
end
end
RSpec.describe MyClass do
it { is_expected.to respond_to(:plant).with_keywords(:seed) }
it { is_expected.to respond_to(:plant).with_keywords(:seed, :fertilizer, :water) }
it { is_expected.not_to respond_to(:plant).with_keywords(:fertilizer, :water) }
# deliberate failures
it { is_expected.not_to respond_to(:plant).with_keywords(:seed) }
it { is_expected.not_to respond_to(:plant).with_keywords(:seed, :fertilizer, :water) }
it { is_expected.to respond_to(:plant).with_keywords(:fertilizer, :water) }
end
"""
When I run `rspec respond_to_matcher_required_keyword_checking_spec.rb`
Then the output should contain all of these:
| 6 examples, 3 failures |
| expected my_object not to respond to :plant with keyword :seed |
| expected my_object not to respond to :plant with keywords :seed, :fertilizer, and :water |
| expected my_object to respond to :plant with keywords :fertilizer and :water |
|
