I’m a newbie to Cucumber framework. I’m trying to call a Ruby method inside of a step definition. Here is how I define my method in lib/methods.rb
class Test_class
def create_test_scenario()
puts "here!!!"
end
end
This is how I try to call the method inside of a step definition:
And(/^I create scenarios$/) do
Test_class.create_test_scenario
end
I'm getting 'uninitialized constant Test_class (NameError)' when I run the test. Any ideas? Thanks.
You haven't instantiated the Test_class object. For example:
class Test_class
def create_test_scenario
puts "here!!!"
end
end
Test_class.new.create_test_scenario # notice `new` method chained here
#=> here!!!
Errata:
Here's a link to documentation that explains the initialize method and how you can use it to set up object state on initialization.
For class (and module) names, the ruby convention is to use CamelCase. For example, TestClass instead of Test_class
As orde has said, this is down to initialization. To help put the code into context, you would initialize the class object in your step definition as an instance variable (which starts with #). So it would look like this:
And(/^I create scenarios$/) do
#Test_class = Test_class.new
#Test_class.create_test_scenario
end
Related
In the Ruby programming language, I am creating a class with a class-level macro, as follows:
class Timer
def self.add_time
def time
STDERR.puts Time.now.strftime("%H:%M:%S")
end
end
end
The class method add_time, when executed, will generate a time method.
Now, I can execute that class-level macro in another class Example as follows:
class Example < Timer
add_time
end
When I now call time on an instance of class Example, the time method is present there, as I intended:
ex = Example.new
ex.time
and prints the current time: 23:18:38.
But now I would like to put the add_time macro in a module and still have the same overall effect. I tried with an include like this:
module Timer
def self.add_time
def time
STDERR.puts Time.now.strftime("%H:%M:%S")
end
end
end
class Example
include Timer
add_time
end
ex = Example.new
ex.time
but then I receive an error that the method add_time is not defined on the class Example: NameError: undefined local variable or method ‘add_time’ for Example:Class. So then I tried with an extend instead like this:
class Example
extend Timer
add_time
end
but it gives me a similar error.
So the question is: How can I get the same effect as in my original example where the Timer was defined as a class, but using a module instead?
As #CarySwoveland pointed out, the method def self.add_time in the module Timer gets disregarded upon inclusion or extension in a class. Only the module's instance methods are added to the class as instance method of the class (in case of inclusion) or as class methods of the class (in case of extends).
module Timer
def add_time # INSTANCE METHOD !
def time
STDERR.puts Time.now.strftime("%H:%M:%S")
end
end
end
So the first step of the solution is to declare the method def add_time as an instance method of the module. Next, we extend the class Example with that module, so that the module's instance method gets added as a class method in the class Example, and we call the add_timemethod:
class Example
extend Timer # EXTEND INSTEAD OF INCLUDE
add_time
end
However, this doesn't quite work as desired yet as the time method has now been generated as a class method: Example.time prints the current time 01:30:37, but an instance ex of class Example does not understand the method time.
The solution is thus to generate the method def time as an instance method rather than as a class method. This can be done using class_eval, which leads us to the following working solution:
module Timer
def add_time # INSTANCE METHOD !
self.class_eval do # USE class_eval TO DEFINE AN INSTANCE METHOD !
def time
STDERR.puts Time.now.strftime("%H:%M:%S")
end
end
end
end
class Example
extend Timer # USE EXTEND TO ADD add_time AS A CLASS METHOD
add_time
end
ex = Example.new
ex.time
I am a beginner in ruby.
I've tried to run this code and it shows run time error.
What's wrong with this code?
class Calc
attr_accessor :val1, :val2
def initialize (val1,val2)
#val1=val1
#val2=val2
end
end
a=Calc.new(2,3)
a.add_two_numbers(3)
def add_two_numbers(v3)
return #val1+#val2+v3
end
The method add_two_numbers is not defined on the class Calc, however you are using it as if it is. This is the problem.
I would presume you got a NoMethodError.
Update: As pointed out in the comments, in actuallity, the method is defined on the Object class by default, which then gets auto inherited into all classes, but as private. This actually means that you will be getting the error saying that a private method is being called. The fix remains the same, since the overarching problem is a confusion in how to define classes and their methods.
The fix would be to define the method on the class, by putting it in the class body.
class Calc
attr_accessor :val1, :val2
def initialize (val1,val2)
#val1=val1
#val2=val2
end
def add_two_numbers(v3)
return #val1+#val2+v3
end
end
So you are defining a method outside of a class (which is want we don't want)
def add_two_numbers(v3)
return #val1+#val2+v3
end
You always want to make sure that you keep your classes and you logic as two separate entities in terms of organization. By that I mean:
Your classes in one file (calc.rb):
**class Calc
attr_accessor :val1, :val2
def initialize (val1,val2)
#val1=val1
#val2=val2
end
def add_two_numbers(v3)
return #val1+#val2+v3
end
end**
And your logic to access calc.rb in another file. Use require relative to access the logic inside the class file:
require_relative"/calc.rb"
a=Calc.new(2,3)
a.add_two_numbers(3)
Tip: When I was learning ruby the best way to keep them in two separate files for better organization.That way you know you don't have a method somewhere outside of the class. This would avoid your "no method error"
I am having a method which returns the price of a given symbol and i am writing a test for that method.
This is my test
def setup
#asset = NetAssetValue.new
end
def test_retrieve_price_for_symbol_YHOO
assert_equal(33.987, #asset.retrieve_price_for_a_symbol('YHOO'))
end
def test_retrive_price_for_YHOO
def self.retrieve_price_for_a_symbol(symbol)
33.77
end
assert_equal(33.97, #asset.retrieve_price_for_a_symbol('YHOO'))
end
This is my method.
def retrieve_price_for_a_symbol(symbol)
symbol_price = { "YHOO" => 33.987, "UPS" => 35.345, "T" => 80.90 }
raise Exception if(symbol_price[symbol].nil?)
symbol_price[symbol]
end
I am trying to mock the retrieve_price_for_a_symbol method by writing same method in test class but when i call it, the call is happening to method in main class not in the test class.
How do I add that method to meta class from test and how do i call it? Please help.
Instead of re-defining the method inside, you need to mock it out.
Replace the method definition inside the test with
#asset.expects(:retrieve_price_for_a_symbol).with('YHOO').returns(33.97)
Assuming you don't really want to mock the method you're testing...
You are currently defining your mock on the instance of the test class. You can add your mock directly to the #asset object:
def test_retrive_price_for_YHOO
def #asset.retrieve_price_for_a_symbol(symbol)
33.77
end
assert_equal(33.97, #asset.retrieve_price_for_a_symbol('YHOO'))
end
I'm trying to create a singleton class that requires some sophisticated initialization. I've boiled my problem down to this test case:
class Dumb
attr_accessor :mything
#my_thing = 1 # this works
self.init_some_stuff # this gives undefined method
class << self
def init_some_stuff
#my_thing = 2
end
def spill_it
puts "My Thing: #{#my_thing}"
end
end
end
I can initialize simple variables, but want to call class methods to do it, and I get "undefined method". Since I intend it to be used as a singleton, a constructor would not get called. What am I missing?
A method is executed whenever it is met.
self.init_some_stuff
is placed before the definition of it. That is the problem. Place it after the definition.
How can I mock the initialize method on a ruby class?
I'm doing some testing and want to mock out the object that is created from a new call.
I tried to write a few things and none of them seemed to get the mock class to return from the new call. It just keeps returning the normal, expected object.
EDIT:
one attempt -
class MockReminderTimingInfoParser < ReminderTimingInfoParser
def new(blank)
ReminderTimingInfoParserForTest.new
end
end
describe ReminderParser do
parser = ReminderParser.new(MockReminderTimingInfoParser)
it "should parse line into a Reminder" do
parser.parse(" doesnt matter \"message\"").should == Reminder.new('message', ReminderTimingInfo.new([DaysOfWeek.new([:sundays])], [1]))
end
end
class ReminderTimingInfoParserForTest
include TimingInfoParser
def parse_section(section); [DaysOfWeek.new([:sundays]), 1] end
def reminder_times_converter(times); times end
end
class MockReminderTimingInfoParser < ReminderTimingInfoParser
def new(blank)
ReminderTimingInfoParserForTest.new
end
end
Here, you are defining a method called new for all instances of the class MockReminderTimingInfoParser. In your question, you mention that you want to hook into instance creation. However, in Ruby, instance creation is not done by instance methods. Obviously, this cannot work, since in order to call an instance method, you'd need to have an instance first!
Instead, instances are created by calling a factory method (commonly called new) on the class.
In other words, in order to create an instance of MockReminderTimingInfoParser, you would call MockReminderTimingInfoParser.new, but you have defined a method MockReminderTimingInfoParser#new. In order to call the method you have defined, you would have to call MockReminderTimingInfoParser.new.new.
You need to define a method on MockReminderTimingInfoParser's singleton class. There's several ways to do that. One way would be just mimicking the way you would call the method:
def MockReminderTimingInfoParser.new(blank)
ReminderTimingInfoParserForTest.new
end
Another would be opening up MockReminderTimingInfoParser's singleton class:
class << MockReminderTimingInfoParser
def new(blank)
ReminderTimingInfoParserForTest.new
end
end
However, in both of these cases, MockReminderTimingInfoParser obviously has to exist first. Given that you need to define the class anyway, here's the most idiomatic way of defining methods on a class's (or module's) singleton class:
class MockReminderTimingInfoParser < ReminderTimingInfoParser
def self.new(blank)
ReminderTimingInfoParserForTest.new
end
end
Could you inherit the class and then supply your own initialize?