Unit Testing - Is it bad form to have unit test calling other unit tests

Question

I have a unit test called TestMakeAValidCall(). It tests my phone app making a valid call.

I am about to write another test called TestShowCallMessage() that needs to have a valid call made for the test. Is it bad form to just call TestMakeAValidCall() in that test?

For reference this is my TestMakeAValidCall() test.

    [TestMethod]     public void TestMakeAValidCall()     {        //Arrange         phone.InCall = false;         phone.CurrentNumber = "";         // Stub the call to the database         data.Expect(x => x.GetWhiteListData()).             Return(FillTestObjects.GetSingleEntryWhiteList());         // Get some bogus data         string phoneNumber = FillTestObjects.GetSingleEntryWhiteList().             First().PhoneNumber;         // Stub th call to MakeCall() so that it looks as if a call was made.         phone.Expect(x => x.MakeCall(phoneNumber)).             WhenCalled(invocation =>                        {                            phone.CurrentNumber = phoneNumber;                            phone.InCall = true;                        });         //Act         // Select the phone number         deviceControlForm.SelectedNumber = phoneNumber;         // Press the call button to make a call.         deviceMediator.CallButtonPressed();         //Assert         Assert.IsTrue(phone.InCall);         Assert.IsTrue(phone.CurrentNumber == phoneNumber);     } 

Answer 1

Refactor the setup to another method and call that method from both tests. Tests should not call other tests.

Answer 2

IMHO, you should do one of the following:

• Create a method that returns a valid call, and use it separately for both tests (not one calling the other)
• Mock the valid call for the ShowCallMessageTest