c# - Nsubstitute: Mocking an object Parameter for Unit Testing -

i new nsubstitute , unit testing. know in unit testing, don't care other dependencies. in order rule applied mock units.

i have example tested code method has object parameter:

class dependency {   public int a;   public dependency() {     // algorithms going on ...     = algorithm_output;   } }  class totest {   public int xa;   public void foo(dependency dep_input){     xa = dep_input.a;     // xa used in algorithm ...   } } 

i thinking of mocking constructor not figure out how in nsubstitute. ultimately, how test this?

i can not add comment because long, add answer: if want test foo not need mock ctor dep_input. example if use moq. can use stub

public interface idependency {     int { get; } }  public class dependency : idependency {     public int { get; private set; }      public dependency()     {         // algorithms going on ...         = algorithm_output();     }      private static int algorithm_output()     {         return 42;     } }  public class totest {     public int xa;      public void foo(idependency dep_input)     {         xa = dep_input.a;         // xa used in algorithm ...     } }  [testfixture] public class testclass {     [test]     public void testwithmoq()     {         var dependecymock = new mock<idependency>();         dependecymock.setup(d => d.a).returns(23);          var totest = new totest();         totest.foo(dependecymock.object);          assert.areequal(23, totest.xa);         dependecymock.verify(d => d.a, times.once);     }      [test]     public void testwithstub()     {         var dependecystub = new dependencytest();          var totest = new totest();         totest.foo(dependecystub);          assert.areequal(23, totest.xa);     }      internal class dependencytest : idependency     {         public int         {                         {                 return 23;             }         }     } }