testing - Writing tests without violating SRP, OCP, DRY -

i trying understand these 3 principles better.

my question is... how write tests without violating srp, ocp, , dry?

my current design violates dry because of similar code in test files.

i can't merge test files because violate open/closed principle. (there high probability of adding more modules later)

is there i'm missing here? if helps i'm using ruby , minitest this.

module files

a.rb:

module   # algorithm end 

b.rb:

module b   #does algorithm end 

test files

a_test.rb:

class moduleatest   # tests algorithm end 

b_test.rb:

class modulebtest   # tests algorithm end 

here how did it. ocp: classes test module not have modified srp: classes test module dry: creating including module tester can avoid duplication of code in tests.

module     def algorithm(foo)         #some implementation      end end  module b     def algorithm(foo)         #some implementation         end end  module module_tester     def test_module_test         assert_equal(@expected, @obj.algorithm(@to_test))         # test them     end end   class moduleatest < test_framework     include module_tester     def before          @obj = object.new.extend(a)         @expected = 'expected outcome goes here'         @to_test = 'the thing test goes here'     end end  class modulebtest < test_framework     include module_tester      def before         @obj = object.new.extend(b)         @expected = 'the expected outcome'         @to_test = 'the thing test'     end end