public static void B_ChangeOfFieldWithValueTypeForComplexValueTypePassedByValueIsNotTakeEffectInCaller()
{
var sourceTrainer = new TrainerValueType("Dan", 2);
var expectedTrainer = sourceTrainer;
Trace.TraceInformation(
$"Create a variable of a complex value type. Type: TrainerValueType, value = '{sourceTrainer}'.");
Trace.TraceInformation("Pass it to the method, which increment property 'Experience' (value type - int).");
var changedTrainer = TypesChanger.IncrementExperienceOfTrainer(sourceTrainer);
Trace.TraceInformation(
"Expected, that the value in the caller is not affected, but the value in the method, " +
"which was called, is incremented. It occurs because the called method got a copy of a complex value type.");
Trace.TraceInformation(
$"Compare the source experience with expected (Should be the same): source = '{sourceTrainer.Experience}'; expected = '{expectedTrainer.Experience}'.");
sourceTrainer.Experience
.Should()
.Be(expectedTrainer.Experience);
Trace.TraceInformation(
$"Compare changed experience with the original (The changed value should be greater than the original): changed = '{changedTrainer.Experience}'; original = '{sourceTrainer.Experience}'.");
changedTrainer.Experience
.Should()
.BeGreaterThan(sourceTrainer.Experience);
}
public static void C_ChangeOfFieldWithReferenceTypeForComplexValueTypePassedByValueIsNotTakeEffectInCaller()
{
var sourceTrainer = new TrainerValueType("Dan", 2);
var expectedTrainer = sourceTrainer;
Trace.TraceInformation(
$"Create a variable of a complex value type with empty field (type of field - reference). Type: TrainerValueType (without trainees), value = '{sourceTrainer}'.");
Trace.TraceInformation(
"Pass it to the method, which add trainees (referenceType type - TraineeReferenceType).");
var changedTrainer = TypesChanger.AssignTraineesToTrainer(sourceTrainer);
Trace.TraceInformation(
"Expected, that the value in the caller is not affected, but the trainer in the method, " +
"which was called, has trainees. It occurs because the called method got a copy of a trainer " +
"no matter the field 'Trainees' is a reference type, the field does not reference to the source reference.");
Trace.TraceInformation(
"Compare trainees of the source trainer with expected (Should be the same and empty): " +
$"source = '{string.Join("; ", sourceTrainer.Trainees.Select(trainee => trainee.ToString()))}'; " +
$"expected = '{string.Join("; ", expectedTrainer.Trainees.Select(trainee => trainee.ToString()))}'.");
// ↑ We use LINQ query here (Select method) we will go deeper with it later, just ignore it for now.
sourceTrainer.Trainees
.Should()
.BeEmpty();
sourceTrainer.Trainees
.Should()
.BeSameAs(expectedTrainer.Trainees);
Trace.TraceInformation(
"The changed trainer should have trainees: " +
$"changed trainees = '{string.Join("; ", changedTrainer.Trainees.Select(trainee => trainee.ToString()))}'.");
changedTrainer.Trainees
.Should()
.OnlyContain(trainee => trainee != null);
}
public static TrainerValueType AssignTraineesToTrainer(TrainerValueType trainer)
{
trainer.Trainees = new[] { new TraineeReferenceType("Bill", 9), new TraineeReferenceType("Bob", 15) };
return(trainer);
}
public static TrainerValueType IncrementExperienceOfTrainer(TrainerValueType trainer)
{
trainer.Experience++;
return(trainer);
}