c# - How to structure my unit test? -

i new unit test , wondering how start testing. application working on, not have unit test. winform application , interested test data layer of application.

here example.

public interface icalculatesomething {      someoutout1 calculatesomething1(someinput1 input1);      someoutout2 calculateosomething2(someinput2 input2); }  public class calculatesomething : icalculatesomething {     someoutout1 icalculatesomething.calculatesomething1(someinput1 input1)     {         someoutout1.prop1 = calculatefrominput1(input1.prop1, input1.prop2);          someoutout1.prop3 = calculatefrominput2(input1.prop3, input1.prop4);          return someoutout1;     }      someoutout2 icalculatesomething.calculateosomething2(someinput2 input2)     {         someoutout2.prop1 = calculatefrominput1(input2.prop1, input2.prop2);          someoutout2.prop3 = calculatefrominput2(input2.prop3, input2.prop4);          return someoutout2;     } } 

i test these 2 methods in calculatesomething. methods implementation long , complicated. how should structure test?

i don't see reason not using straight-forward unit test implementation. i'd start basic test method:

[testmethod] public void calculatesomething1_fooinput {     var input = new someinput1("foo");     var expected = new someoutput1(...);      var calc = new calculatesomething(...);     var actual = calc.calculatesomething1(input);      assert.areequal(expected.prop1, actual.prop1);     assert.areequal(expected.prop2, actual.prop2);     assert.areequal(expected.prop3, actual.prop3); } 

and then, add calculatesomething1_barinput , calculatesomething2_fooinput, factor out common code helper methods:

[testmethod] public void calculatesomething1_fooinput {     var input = new someinput1("foo");     var expected = new someoutput1(...);      var actual = createtestcalculatesomething().calculatesomething1(input);      assertsomeoutput1equality(expected, actual); }