Learn how to write simple tests

ruby-talk
1

Hello,

Im now trying to do the first exercises of codewars.
The exercises are not a problem.

As I example I use the hello world programm.

I can write

def greeter
    puts "Hello World!"
end

But how on earth can I make a test-case for this using for example assert ?

Roelof

2

You can test that the `greeter` method returns hello world, on ruby
1.9.3+ like this (run `ruby greeter_test.rb`):

    # greeter.rb
    def greeter
      "Hello World!"
    end

    # greeter_test.rb
    require "minitest/autorun"
    require_relative "greeter"

    class SimpleTest < Minitest::Unit::TestCase
      def test_greeter
        assert_equal greeter, "Hello World!"
      end
    end

Testing that it calls puts with the "Hello World!" args is more
difficult.

···

On Mon, May 26, 2014 at 10:44:13PM +0200, Roelof Wobben wrote:

But how on earth can I make a test-case for this using for example assert ?

3

Amadeus Folego schreef op 26-5-2014 22:59:

···

On Mon, May 26, 2014 at 10:44:13PM +0200, Roelof Wobben wrote:

But how on earth can I make a test-case for this using for example assert ?

You can test that the `greeter` method returns hello world, on ruby
1.9.3+ like this (run `ruby greeter_test.rb`):

     # greeter.rb
     def greeter
       "Hello World!"
     end

     # greeter_test.rb
     require "minitest/autorun"
     require_relative "greeter"

     class SimpleTest < Minitest::Unit::TestCase
       def test_greeter
         assert_equal greeter, "Hello World!"
       end
     end

Testing that it calls puts with the "Hello World!" args is more
difficult.

hmm ,
When I do this solution I see this eror :
NoMethodError: undefined method `require' for main:Object

when I do the assert_equal line alone I see this error :
NoMethodError: undefined method `assert_equal' for main:Object

Roelof

4

It is easy with - Module: Test::Unit::Assertions (Ruby 2.1.1)

assert_equal "Hello World!", greeter

···

On Monday, May 26, 2014 10:44:13 PM Roelof Wobben wrote:

Hello,

Im now trying to do the first exercises of codewars.
The exercises are not a problem.

As I example I use the hello world programm.

I can write

def greeter
    puts "Hello World!"
end

But how on earth can I make a test-case for this using for example assert ?

Roelof

--

Regards,
Arup Rakshit

5

Which ruby version are you using?

On 2.1.1 it runs fine.

···

On Mon, May 26, 2014 at 11:20:14PM +0200, Roelof Wobben wrote:

Amadeus Folego schreef op 26-5-2014 22:59:
>On Mon, May 26, 2014 at 10:44:13PM +0200, Roelof Wobben wrote:
>>But how on earth can I make a test-case for this using for example assert ?
>You can test that the `greeter` method returns hello world, on ruby
>1.9.3+ like this (run `ruby greeter_test.rb`):
>
> # greeter.rb
> def greeter
> "Hello World!"
> end
>
> # greeter_test.rb
> require "minitest/autorun"
> require_relative "greeter"
>
> class SimpleTest < Minitest::Unit::TestCase
> def test_greeter
> assert_equal greeter, "Hello World!"
> end
> end
>
>Testing that it calls puts with the "Hello World!" args is more
>difficult.
>

hmm ,
When I do this solution I see this eror :
NoMethodError: undefined method `require' for main:Object

when I do the assert_equal line alone I see this error :
NoMethodError: undefined method `assert_equal' for main:Object

Roelof

6

If you are doing it in codewars the chances are they undefined require. The testing advice here is given for normal execution.

Mistral

···

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

Amadeus Folego schreef op 26-5-2014 22:59:

On Mon, May 26, 2014 at 10:44:13PM +0200, Roelof Wobben wrote:

But how on earth can I make a test-case for this using for example assert ?

You can test that the `greeter` method returns hello world, on ruby
1.9.3+ like this (run `ruby greeter_test.rb`):

    # greeter.rb
    def greeter
      "Hello World!"
    end

    # greeter_test.rb
    require "minitest/autorun"
    require_relative "greeter"

    class SimpleTest < Minitest::Unit::TestCase
      def test_greeter
        assert_equal greeter, "Hello World!"
      end
    end

Testing that it calls puts with the "Hello World!" args is more
difficult.

hmm ,
When I do this solution I see this eror :
NoMethodError: undefined method `require' for main:Object

when I do the assert_equal line alone I see this error :
NoMethodError: undefined method `assert_equal' for main:Object

Roelof

7

Mistral CONTRASTIN schreef op 26-5-2014 23:40:

If you are doing it in codewars the chances are they undefined require. The testing advice here is given for normal execution.

Mistral

Im working on codewars. I will try to ask them for some help.

Roelof

···

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

8

Mistral CONTRASTIN schreef op 26-5-2014 23:40:

If you are doing it in codewars the chances are they undefined require. The testing advice here is given for normal execution.

Mistral

Thanks,

Can anyone help me figure out why I see here a syntax error :

class Testgreeter > Test:Unit:TestCase

     def test
        assert_equal("Hello World!", "output is not Hello World")
     end
end

Roelof

···

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

9

Mistral CONTRASTIN schreef op 26-5-2014 23:40:

If you are doing it in codewars the chances are they undefined require. The testing advice here is given for normal execution.

Mistral

Thanks,

Can anyone help me figure out why I see here a syntax error :

class Testgreeter > Test:Unit:TestCase

Try: class Testgreeter < Test:Unit:TestCase

   def test
      assert_equal("Hello World!", "output is not Hello World")
   end
end

Roelof

Panagiotis (atmosx) Atmatzidis

email: atma@convalesco.org
URL: http://www.convalesco.org
GnuPG ID: 0x1A7BFEC5
gpg --keyserver pgp.mit.edu --recv-keys 1A7BFEC5

"As you set out for Ithaca, hope the voyage is a long one, full of adventure, full of discovery [...]" - C. P. Cavafy

···

On 27 Μαϊ 2014, at 09:31 , Roelof Wobben <r.wobben@home.nl> wrote:

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

10

Panagiotis Atmatzidis schreef op 27-5-2014 9:41:

···

On 27 Μαϊ 2014, at 09:31 , Roelof Wobben <r.wobben@home.nl> wrote:

Mistral CONTRASTIN schreef op 26-5-2014 23:40:

If you are doing it in codewars the chances are they undefined require. The testing advice here is given for normal execution.

Mistral

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

Thanks,

Can anyone help me figure out why I see here a syntax error :

class Testgreeter > Test:Unit:TestCase

Try: class Testgreeter < Test:Unit:TestCase

    def test
       assert_equal("Hello World!", "output is not Hello World")
    end
end

Roelof

Changed it and still the syntax error message.

Roelof

11

Oh...
":" -> "::"

Try this code:
class Testgreeter < Test::Unit::TestCase
end

···

2014-05-27 11:46 GMT+04:00 Roelof Wobben <r.wobben@home.nl>:

Panagiotis Atmatzidis schreef op 27-5-2014 9:41:

On 27 Μαϊ 2014, at 09:31 , Roelof Wobben <r.wobben@home.nl> wrote:

Mistral CONTRASTIN schreef op 26-5-2014 23:40:

If you are doing it in codewars the chances are they undefined require.
The testing advice here is given for normal execution.

Mistral

On 26 May 2014, at 22:20, Roelof Wobben <r.wobben@home.nl> wrote:

Thanks,

Can anyone help me figure out why I see here a syntax error :

class Testgreeter > Test:Unit:TestCase

Try: class Testgreeter < Test:Unit:TestCase

    def test
       assert_equal("Hello World!", "output is not Hello World")
    end
end

Roelof

Changed it and still the syntax error message.

Roelof

--
С уважением, Шурмин Евгений

12

Евгений Шурмин schreef op 27-5-2014 10:33:

Oh...
":" -> "::"

Try this code:
class Testgreeter < Test::Unit::TestCase
end

found it after a little bit trying.

the right answer is :

but now I have this :

def no_odds( values )
   values.select { |x| x.even?}
end

and these test cases :

Test.assert_equals([2] , no_odds([2]))
Test.assert_raise(NoMethodError , no_odds(["a"]), "Er bestaat geen ?even voor een string")

Still I see this error message :

NoMethodError: undefined method `even?' for "a":String

NoMethodError: undefined method `even?' for "a":String

How can I take care that my error message is shown or even that there is no error message too seen as I run the tests.

Roelof

13

I don't know 'even?' method.
Look here about all methods of String class:

···

2014-05-27 13:50 GMT+04:00 Roelof Wobben <r.wobben@home.nl>:

Евгений Шурмин schreef op 27-5-2014 10:33:

Oh...
":" -> "::"

Try this code:
class Testgreeter < Test::Unit::TestCase
end

found it after a little bit trying.

the right answer is :

but now I have this :

def no_odds( values )
  values.select { |x| x.even?}
end

and these test cases :

Test.assert_equals([2] , no_odds([2]))
Test.assert_raise(NoMethodError , no_odds(["a"]), "Er bestaat geen ?even
voor een string")

Still I see this error message :

NoMethodError: undefined method `even?' for "a":String

NoMethodError: undefined method `even?' for "a":String

How can I take care that my error message is shown or even that there is no
error message too seen as I run the tests.

Roelof

14

Test.assert_equals([2] , no_odds([2]))
Test.assert_raise(NoMethodError , no_odds(["a"]), "Er bestaat geen ?even
voor een string")

Still I see this error message :

NoMethodError: undefined method `even?' for "a":String

NoMethodError: undefined method `even?' for "a":String

How can I take care that my error message is shown or even that there is
no error message too seen as I run the tests.

I think you confuse the reason for a unit test with a syntactic test. The unit
test asserts that your syntactic correct code produces the desired results.

Basically, your code:

Test.assert_raise(NoMethodError , no_odds(["a"]))

Says this: "I don't trust the Ruby Interpreter, so I want to write a test
where I check whether the interpreter finds out that there's no #even? for a
string or not". This is not what unit testing is supposed to do.

*If* you had extra safeguards in your code, you could check them. For example,
consider this:

---%<---
def no_odds(values)
  return unless values.class == Array
  values.select { |x| x.respond_to? :even? && x.even?}
end
--->%---

Now you could test whether your code works right:

---%<---
assert_equal , no_odds(2)
assert_equal [2], no_odds([1, 2, "a", "c", 3])
--->%---

HTH

      --- Eric

···

On Tuesday 27 May 2014 11:50:15, Roelof Wobben <r.wobben@home.nl> wrote:

15

Excuse the typo:

---%<---
def no_odds(values)
  return unless values.class == Array
  values.select { |x| x.respond_to? :even? && x.even?}
end
--->%---

Should be:

---%<---
def no_odds(values)
  return unless values.class == Array
  values.select {|x| x.respond_to?(:even?) && x.even? }
end
--->%---

Note the parentheses.

    --- Eric

···

On Tuesday 27 May 2014 15:11:54, Eric MSP Veith <eveith@wwweb-library.net> wrote:

16

Curious. How do you test a function embedded in another function?