public async void Option1____WhenGivenADateTimeOtherThanMinValue_ShouldPassItToRepository()
{
/* Option 1
* ================
*
* To inspect the expression passed in, we'll use a Callback in Moq to interrogate the parameter sent to
* the Repository's GetItems method.
*
* Rather than parse the Expression Tree, we'll compile it and pass in some values that would prove it's
* doing what we expect.
*
* I'm not a big fan of this, since we're "blackbox" testing the Expression, which works, but isn't ideal.
*
* Also, this test is now HUGE in comparison to other tests.
*/
// Arrange
// Note: Rather than using just "DateTime.Today", I'm randomizing the date. This way, if the SUT has
// "DateTime.Today" hardcoded, the test will fail.
var rando = new Random().Next(1, 100);
var input = DateTime.Today.AddDays(rando);
var repository = new Mock <IFiscalDataRepository>();
repository
.Setup(x => x.GetItems(It.IsAny <Expression <Func <IFiscalData, bool> > >()))
.Returns(Task.FromResult((IEnumerable <IFiscalData>) new IFiscalData[] { }))
.Callback <Expression <Func <IFiscalData, bool> > >(expr =>
{
// Assert
var compiledExpr = expr.Compile();
var matchingDate = new FiscalData {
Date = input
};
var nonMatchingDate1 = new FiscalData {
Date = input.AddDays(1)
};
var nonMatchingDate2 = new FiscalData {
Date = input.AddDays(-1)
};
var matchingResult = compiledExpr(matchingDate);
var nonMatchingResult1 = compiledExpr(nonMatchingDate1);
var nonMatchingResult2 = compiledExpr(nonMatchingDate2);
Assert.True(matchingResult);
Assert.False(nonMatchingResult1);
Assert.False(nonMatchingResult2);
});
// Act
var service = new FiscalDataService(repository.Object, null);
await service.GetFiscalData(input);
}
public async void WhenNullReturnedFromRepository_ShouldThrowNoDataFoundException()
{
// Arrange
var repository = new Mock <IFiscalDataRepository>();
repository
.Setup(x => x.GetItems(It.IsAny <Expression <Func <IFiscalData, bool> > >()))
.Returns(Task.FromResult((IEnumerable <IFiscalData>)null));
// Act + Assert
var service = new FiscalDataService(repository.Object, null);
await Assert.ThrowsAsync <NoDataFoundException>(
async() => { await service.GetFiscalData(DateTime.Now); }
);
}
public async void ShouldReturnTheFiscalDataObjectFromTheRepository()
{
// Arrange
var expected = new FiscalData();
var repository = new Mock <IFiscalDataRepository>();
repository
.Setup(x => x.GetItems(It.IsAny <Expression <Func <IFiscalData, bool> > >()))
.Returns(Task.FromResult((IEnumerable <IFiscalData>) new[] { expected }));
// Act
var service = new FiscalDataService(repository.Object, null);
var actual = await service.GetFiscalData(DateTime.Today);
// Assert
Assert.Equal(expected, actual);
}
public async void ShouldCallTheRepositorysGetItemsMethod()
{
// Arrange
var repository = new Mock <IFiscalDataRepository>();
repository
.Setup(x => x.GetItems(It.IsAny <Expression <Func <IFiscalData, bool> > >()))
.Returns(Task.FromResult((IEnumerable <IFiscalData>) new List <IFiscalData>()))
.Verifiable();
// Act
var service = new FiscalDataService(repository.Object, null);
await service.GetFiscalData(DateTime.Today);
// Assert
repository.Verify();
}
public async void Option2____WhenGivenADateTimeOtherThanMinValue_ShouldPassItToRepository()
{
/* Option 2
* ================
*
* To inspect the expression passed in, we'll use a Callback in Moq to interrogate the
* parameter sent to the Repository's GetItems method.
*
* If we know (and we should) that the Expression used will be a BinaryExpression with the
* variable on the Right side, we can grab, then compile, that piece and compare its value
* to our input.
*
* This method is not perfect either, as it's convoluted to write - especially before coding
* the class - and I can see annoying maintenance issues with it. That said, it probably is a
* better test than Option1, as its "whitebox" nature helps reduce false positives.
*
*/
// Arrange
var input = DateTime.Today.AddDays(new Random().Next(1, 100));
var repository = new Mock <IFiscalDataRepository>();
repository
.Setup(x => x.GetItems(It.IsAny <Expression <Func <IFiscalData, bool> > >()))
.Returns(Task.FromResult((IEnumerable <IFiscalData>) new IFiscalData[] { }))
.Callback <Expression <Func <IFiscalData, bool> > >(expr =>
{
// Assert
var memberExpr = (expr.Body as BinaryExpression)?.Right as MemberExpression;
// Using Assert.True(...) as xUnit doesn't support messages on Assert.NotNull(...)
Assert.True(memberExpr != null, "Unable to convert expression into usable form");
var exprValue = memberExpr.GetValue();
Assert.Equal(input, exprValue);
});
// Act
var service = new FiscalDataService(repository.Object, null);
await service.GetFiscalData(input);
}