Method Arguments Lab
Objectives
- Define a method that takes in an argument and uses that argument in the method body.
- Define a method that takes in two arguments and uses both arguments in the method body.
Instructions
You'll be coding your methods in lib/introduction.rb
.
#introduction
Method
The Run the test suite to get started. To do that, run learn
or learn test
in your terminal. Let's take a look at the first error:
Failures:
1) #introduction takes in an argument of a name and puts out a phrase with that name using string interpolation
Failure/Error: expect{introduction("Josh")}.to output("Hi, my name is Josh.\n").to_stdout
NoMethodError:
undefined method `introduction' for #<RSpec::ExampleGroups::Introduction:0x007fdbc499a938>
# ./spec/introduction_spec.rb:5:in `block (3 levels) in <top (required)>'
# ./spec/introduction_spec.rb:5:in `block (2 levels) in <top (required)>'
Wow, that's a lot of information. The important part for us though is the line that tells us what kind of error we are experiencing:
NoMethodError:
undefined method `introduction'
Looks like our test is expecting to test a method called #introduction
. Let's define that method in lib/introduction.rb
.
# lib/introduction.rb
def introduction
end
Now we'll run our test suite again. You should see the following error:
Failures:
1) #introduction takes in an argument of a name and puts out a phrase with that name using string interpolation
Failure/Error: expect{introduction("Josh")}.to output("Hi, my name is Josh.\n").to_stdout
ArgumentError:
wrong number of arguments (1 for 0)
# ./lib/introduction.rb:9:in `introduction'
# ./spec/introduction_spec.rb:5:in `block (3 levels) in <top (required)>'
# ./spec/introduction_spec.rb:5:in `block (2 levels) in <top (required)>'
Once again the important part of this error message is the part where the type of error is described:
ArgumentError:
wrong number of arguments (1 for 0)
Now we have an ArgumentError. The test is trying to call our #introduction
method with an argument (notice it says 1
) but we haven't defined our method to take in any arguments, the for 0
part of the error message.
Let's fix that now:
# lib/introduction.rb
def introduction(name)
end
Run the test again and you'll see the following:
Failures:
1) #introduction takes in an argument of a name and puts out a phrase with that name using string interpolation
Failure/Error: expect{introduction("Josh")}.to output("Hi, my name is Josh.\n").to_stdout
expected block to output "Hi, my name is Josh.\n" to stdout, but output nothing
Diff:
@@ -1,2 +1 @@
-Hi, my name is Josh.
# ./spec/introduction_spec.rb:5:in `block (2 levels) in <top (required)>'
Now the important part of our error message is here:
expected block to output "Hi, my name is Josh.\n" to stdout, but output nothing
Our test is expecting our method to puts
out the exact phrase, using the value of the name
argument that the method is called with.
Let's fix that:
# lib/introduction.rb
def introduction(name)
puts "Hi, my name is #{name}."
end
Run the test again and we should be passing the first of our two tests. Use the test output and the procedure we just followed to get the second test passing.
#introduction_with_language
Method
The Define a method, #introduction_with_language
that takes in two arguments, name
and language
and outputs the phrase: `"Hi, my name is #{name} and I am learning to program in #{language}."
View Method Arguments Lab on Learn.co and start learning to code for free.