Learning how to Rspec 3. I have a question on the matchers. The tutorial i am following is based on Rspec 2.
describe Team do
it "has a name" do
#Team.new("Random name").should respond_to :name
expect { Team.new("Random name") }.to be(:name)
end
it "has a list of players" do
#Team.new("Random name").players.should be_kind_of Array
expect { Team.new("Random name").players }.to be_kind_of(Array)
end
end
Why is the code causing an error while the one i commented out passing with depreciation warning.
Error
Failures:
1) Team has a name
Failure/Error: expect { Team.new("Random name") }.to be(:name)
You must pass an argument rather than a block to use the provided matcher (equal :name), or the matcher must implement `supports_block_expectations?`.
# ./spec/team_spec.rb:7:in `block (2 levels) in <top (required)>'
2) Team has a list of players
Failure/Error: expect { Team.new("Random name").players }.to be_kind_of(Array)
You must pass an argument rather than a block to use the provided matcher (be a kind of Array), or the matcher must implement `supports_block_expectations?`.
# ./spec/team_spec.rb:13:in `block (2 levels) in <top (required)>'
You should use normal brackets for those tests:
expect(Team.new("Random name")).to eq :name
When you use curly brackets, you are passing a block of code. For rspec3 it means that you will put some expectations about the execution of this block rather than on the result of execution, so for example
expect { raise 'hello' }.to raise_error
EDIT:
Note however that this test will fail, as Team.new returns an object, not a symbol. You can modify your test so it passes:
expect(Team.new("Random name")).to respond_to :name
# or
expect(Team.new("Random name").name).to eq "Random name"
Related
I'm not able to understand why the following Rspec test does not pass -
require "rspec"
require_relative "file-to-be-tested"
describe Customer do
it "is valid with firstname" do
customer = Customer.new("handy")
expect(customer).to be_valid
end
end
for the corresponding Class definition -
class Customer
attr_reader :firstname
def initialize(firstname)
#firstname = firstname
end
end
these two code snippets are in separate files in the same folder, so when i run ~rspec <first-filename> in the terminal, I get the following error -
F
Failures:
1) Customer is valid with firstname
Failure/Error: expect(customer).to be_valid
expected #<Customer:0x007f90e50f3110> to respond to `valid?`
# ./poodr/poodr_rspec.rb:8:in `block (2 levels) in <top (required)>'
Finished in 0.00551 seconds (files took 0.52876 seconds to load)
1 example, 1 failure
Failed examples:
rspec ./poodr/poodr_rspec.rb:6 # Customer is valid with firstname
be_valid is an rspec-rails method, but it looks like you're using just straight rspec. you could do something like:
require "rspec"
require_relative "file-to-be-tested"
describe Customer do
it "is valid with firstname" do
expect { Customer.new('handy') }.to_not raise_error
end
end
What are you expecting the to be_valid test to do? The issue is that the Customer class has no method called valid? which your test is trying to test.
A hack to move your test along if your doing test driven development:
class Customer
def valid?
true
end
end
You now have a method called valid and your test will pass. Obviously it shouldn't always be true so your next step would be to expand the definition of valid?. What check needs to be done to know if a customer is valid or not?
I have an rspec test on a pure Ruby model:
require 'spec_helper'
require 'organization'
describe Organization do
context '#is_root?' do
it "creates a root organization" do
org = Organization.new
expect { org.is_root?.to eq true }
end
end
end
My organization model looks like this:
class Organization
attr_accessor :parent
def initialize(parent = nil)
self.parent = parent
end
end
The output when running the tests:
bundle exec rspec spec/organization_spec.rb:6
Run options: include {:locations=>{"./spec/organization_spec.rb"=>[6]}}
.
Finished in 0.00051 seconds
1 example, 0 failures
When I run the test, it passes, despite the fact that the method is_root? doesn't exist on the model. I usually work in Rails, not pure Ruby, and I've never seen this happen. What is going on?
Thanks!
It should be:
expect(org.is_root?).to eq true
When you pass block to expect it is being wrapped in ExpectationTarget class (strictly speaking BlockExpectationTarget < ExpectationTarget). Since you didn't specify what you expect from this object, the block is never executed, hence no error is raised.
You are passing a block to expect, which is never being called. You can see this by setting an expectation on that block
expect { org.is_root?.to eq true }.to_not raise_error
1) Organization#is_root? creates a root organization
Failure/Error: expect { puts "HI";org.is_root?.to eq true }.to_not raise_error
expected no Exception, got #<NoMethodError: undefined method `is_root?' for #<Organization:0x007ffa798c2ed8 #parent=nil>> with backtrace:
# ./test_spec.rb:15:in `block (4 levels) in <top (required)>'
# ./test_spec.rb:15:in `block (3 levels) in <top (required)>'
# ./test_spec.rb:15:in `block (3 levels) in <top (required)>'
Or by just putting a plain raise or puts inside the block, neither of which will be called:
expect { puts "HI"; raise; org.is_root?.to eq true }
The block form is used for expecting that a piece of code raises an exception or not. The correct syntax for checking values is:
expect(org.is_root?).to eq(true)
Just learning rspec syntax and I noticed that this code works:
context "given a bad list of players" do
let(:bad_players) { {} }
it "fails to create given a bad player list" do
expect{ Team.new("Random", bad_players) }.to raise_error
end
end
But this code doesn't:
context "given a bad list of players" do
let(:bad_players) { {} }
it "fails to create given a bad player list" do
expect( Team.new("Random", bad_players) ).to raise_error
end
end
It gives me this error:
Team given a bad list of players fails to create given a bad player list
Failure/Error: expect( Team.new("Random", bad_players) ).to raise_error
Exception:
Exception
# ./lib/team.rb:6:in `initialize'
# ./spec/team_spec.rb:23:in `new'
# ./spec/team_spec.rb:23:in `block (3 levels) in <top (required)>'
My question is:
Why does this happen?
What is the difference between the former and later example exactly in ruby?
I am also looking for rules on when to use one over the other
One more example of the same but inverse results, where this code works:
it "has a list of players" do
expect(Team.new("Random").players).to be_kind_of Array
end
But this code fails
it "has a list of players" do
expect{ Team.new("Random").players }.to be_kind_of Array
end
Error I get in this case is:
Failure/Error: expect{ Team.new("Random").players }.to be_kind_of Array
expected #<Proc:0x007fbbbab29580#/Users/amiterandole/Documents/current/ruby_sandbox/tdd-ruby/spec/team_spec.rb:9> to be a kind of Array
# ./spec/team_spec.rb:9:in `block (2 levels) in <top (required)>'
The class I am testing looks like this:
class Team
attr_reader :name, :players
def initialize(name, players = [])
raise Exception unless players.is_a? Array
#name = name
#players = players
end
end
As has been mentioned:
expect(4).to eq(4)
This is specifically testing the value that you've sent in as the parameter to the method. When you're trying to test for raised errors when you do the same thing:
expect(raise "fail!").to raise_error
Your argument is evaluated immediately and that exception will be thrown and your test will blow up right there.
However, when you use a block (and this is basic ruby), the block contents isn't executed immediately - it's execution is determined by the method you're calling (in this case, the expect method handles when to execute your block):
expect{raise "fail!"}.to raise_error
We can look at an example method that might handle this behavior:
def expect(val=nil)
if block_given?
begin
yield
rescue
puts "Your block raised an error!"
end
else
puts "The value under test is #{val}"
end
end
You can see here that it's the expect method that is manually rescuing your error so that it can test whether or not errors are raised, etc. yield is a ruby method's way of executing whatever block was passed to the method.
In the first case, when you pass a block to expect, the execution of the block doesn't occur until it's time to evaluate the result, at which point the RSpec code can catch any error that are raised and check it against the expectation.
In the second case, the error is raised when the argument to expect is evaluated, so the expect code has no chance to get involved.
As for rules, you pass a block or a Proc if you're trying to test behavior (e.g. raising errors, changing some value). Otherwise, you pass a "conventional" argument, in which case the value of that argument is what is tested.
I'm having problems getting this simple test to pass on RSpec 2.8.
I want to write a simple test for the absence of parameters on a method that requires them (i.e. ArgumentError: wrong number of arguments ('x' for 'y')).
My test is testing a Gem module method like so:
describe "#ip_lookup" do
it "should raise an ArgumentError error if no parameters passed" do
expect(#geolocater.ip_lookup).to raise_error(ArgumentError)
end
end
My gem module code looks like this:
module Geolocater
def ip_lookup(ip_address)
return ip_address
end
end
My spec runs with this output.
Failure/Error: expect(#geolocater.ip_lookup).to raise_error(ArgumentError)
ArgumentError:
wrong number of arguments (0 for 1)
# ./lib/geolocater.rb:4:in `ip_lookup'
# ./spec/geolocater_spec.rb:28:in `block (3 levels) in <top (required)>'
What am I missing here?
You need to pass a block to #expect, not a regular argument:
describe "#ip_lookup" do
it "should raise an ArgumentError error if no parameters passed" do
expect { #geolocater.ip_lookup }.to raise_error(ArgumentError)
end
end
I have a problem with mocking. I have class DistanceMatrix and I would
like to indicate which method form_matrix was called in if/else
statement. I need to use mocha and RSpec. Any ideas?
class DistanceMatrix
def initialize(*args)
if args[0].class == String
form_matrix(get_data_from_yaml(args[0], args[1]))
elsif args[0].class == Array || args[0] == nil
form_matrix(get_data_from_db(args[0]))
end
end
def form_matrix(...)
...
end
end
it tried:
describe DistanceMatrix, "when mocking ..." do
it "should do call form_matrix" do
DistanceMatrix.any_instance.expects(:form_matrix).with([1]).once
DistanceMatrix.any_instance.expects(:get_data_from_yaml).with("file_name.yml").once.returns([1])
DistanceMatrix.new("file_name.yml")
end
end
but got error:
Failures:
1) DistanceMatrix when mocking ... should do call form_matrix
Failure/Error: DistanceMatrix.new("file_name.yml")
unexpected invocation: #<AnyInstance:DistanceMatrix>.get_data_from_yaml('file_name.yml', nil)
unsatisfied expectations:
- expected exactly once, not yet invoked: #<AnyInstance:DistanceMatrix>.get_data_from_yaml('file_name.yml')
- expected exactly once, not yet invoked: #<AnyInstance:DistanceMatrix>.form_matrix([1])
satisfied expectations:
- allowed any number of times, already invoked once: #<DistanceMatrix:0x9e48b40>.get_optimal_route(any_parameters)
- allowed any number of times, already invoked once: #<Database::Distances:0x9d59798>.load_distances(any_parameters)
# ./distance_matrix.rb:18:in `initialize'
# ./tsp_algorithm_spec.rb:253:in `new'
# ./tsp_algorithm_spec.rb:253:in `block (2 levels) in <top (required)>'
Finished in 0.25979 seconds
I found that in RSpec we should use not .expects() but .should_receive(), so I tried:
describe DistanceMatrix, "when mocking ..." do
it "should do call form_matrix" do
DistanceMatrix.any_instance.should_receive(:form_matrix).with([1])
DistanceMatrix.any_instance.should_receive(:get_data_from_yaml).with("file_name.yml").and_return([1])
DistanceMatrix.new("file_name.yml")
end
end
but got new failure:
Failures:
1) DistanceMatrix when mocking ... should do call form_matrix
Failure/Error: DistanceMatrix.any_instance.should_receive(:form_matrix).with([1])
(#<Mocha::ClassMethods::AnyInstance:0x96356b0>).form_matrix([1])
expected: 1 time
received: 0 times
# ./tsp_algorithm_spec.rb:251:in `block (2 levels) in <top (required)>'
Finished in 0.26741 seconds
I only have experience with using Mocha and not RSpec, but looking at the Mocha failure message, the key parts are these :-
unexpected invocation: #<AnyInstance:DistanceMatrix>.get_data_from_yaml('file_name.yml', nil)
unsatisfied expectations:
- expected exactly once, not yet invoked: #<AnyInstance:DistanceMatrix>.get_data_from_yaml('file_name.yml')
If you look at the ends of these lines, you will notice that get_data_from_yaml is not being called with the expected parameters. It is being called with ('filename.yml', nil) and not ('filename.yml') as expected.
This is happening because when you call DistanceMatrix.new("file_name.yml") in your test with only one argument and then inside DistanceMatrix#initialize DistanceMatrix#get_data_from_yaml is being called with (args[0], args[1]) and since args is a single element array, args[1] will be nil.
Maybe this isn't how you expected Ruby to work, but the following demonstrates this behaviour :-
def foo(*args)
puts "args[0]=#{args[0].inspect}; args[1]=#{args[1].inspect}"
end
foo("string") # => args[0]="string"; args[1]=nil
DistanceMatrix.any_instance.expects(:form_matrix).with("String") # => supply the correct string param
or
DistanceMatrix.any_instance.expects(:form_matrix).with([]) # => supply the correct array param
I'm not sure what your get_data_from_db and get_data_from_yaml methods are doing, but you should be able to control those inputs as well to verify the correct arguments are being supplied to form_matrix.
EDITED
You'll have to use DistanceMatrix.any_instance instead of mocking on an instance variable because you're trying to mock something in the initializer. Also, in case its unclear, you'll need to actually make the appropriate method call after you set up the mock in the lines above, e.g.
DistanceMatrix.new("SomeString")
EDITED
it "should do call #form_matrix with proper arguments" do
DistanceMatrix.any_instance.expects(:form_matrix).with([1])
DistanceMatrix.any_instance.expects(:get_data_from_yaml).with("foo").returns([1])
DistanceMatrix.new("foo")
end