I am writing a unit test and in it trying to setup a simple generic list containg mocks of an entity class...
Dim schedules = New List(Of Schedule) From
{
Mock.Of(Of Schedule)(Function(s) s.ActiveFrom = "2010-01-01" AndAlso
s.ActiveUntil = New DateTime?("2110-01-01"))
}
Schedule.ActiveFrom is a Date and Schedule.ActiveUntill is a Nullable(Of Date).
When i run the unit test i get the following error message...
The binary operator AndAlso is not defined for the types 'System.Nullable[System.Boolean] >and System.Boolean
I'm stumped; Where am I going wrong?
This isn't of much help to your VB Unit test, but the C# equivalent works just fine:
var schedules = new List<Schedule>
{
Mock.Of<Schedule>(
s => s.ActiveFrom == new DateTime(2010, 01, 01)
&& s.ActiveUntil == new Nullable<DateTime>(new DateTime(2110, 01, 01)))
};
Assert.IsTrue((schedules.Count == 1) &&
schedules.Single(_ => (_.ActiveFrom == new DateTime(2010, 01, 01))
&& (_.ActiveUntil == new DateTime(2110, 01, 01))) != null);
It also isn't related to the implicit comparison of DateTime to DateTime? either as careful unpacking of the DateTime? also fails:
AndAlso If(Not s.ActiveUntil.HasValue, False,
s.ActiveUntil.Value = New DateTime("2110-01-01")
I believe the issue may relate to Mock.Of's usage of parsed Expressions during construction of the mock from the predicate provided - possibly there is nuance in VB which wasn't considered.
If so, and assuming you don't want to change your unit tests to C#, you may need to either need to build the Expressions by hand to get the Mock.Of(predicate) goodness to work, or revert to old style creation of your Mock / Fake objects:
Dim scheduleMock As New Mock(Of Schedule)
scheduleMock.SetupGet(Function(s) s.ActiveFrom).Returns("2010-01-01")
scheduleMock.SetupGet(Function(s) s.ActiveUntil).Returns(New DateTime?("2110-01-01"))
Dim schedules = New List(Of Schedule) From
{
scheduleMock.Object
}
Assert.IsTrue(schedules.Count = 1)
Assert.IsTrue(schedules.First.ActiveFrom = "2010-01-01"
AndAlso schedules.First.ActiveUntil = "2110-01-01")
The problem is that you actually have two different types. VB can't handle that. So you want to trap the nullable portion and if it is null, return a straight boolean.
One thing you can do is change:
s.ActiveUntil = New DateTime?("2110-01-01")
to
if(s.ActiveUntil is Nothing, FALSE, s.ActiveUntil = New DateTime?("2110-01-01"))
This way, if the field is null, a simple boolean is returned, and if it is not null, you can return the boolean results of the compare.
Related
I do have the following VB.NET code:
Dim list = directoryQuery.Select(
Function(d) New With {
.dir = d.FullName,
.acl = GetFileSystemAccessRule(d).Select(
Function(a) New With {.if = a.Reference.ToString()}
)
}
)
End Sub
Sometimes the return of GetFileSystemAccessRule(d).Select is Return Enumerable.Empty(Of FileSystemAccessRule)(). In that case, I would like to neither add .directory nor .acl to that list. I want to skip it.
So I tought about the options to remove afterwards the empty items.
//tried but failed:
list = list.Where(Function(a) a.acl IsNot Enumerable.Empty(list)).ToList()
//tried but failed:
list = list.Where(Function(a) a.acl IsNot Nothing).ToList()
But unfortunately all of them failed. What do I wrong?
I think this would be the way to go:
list = list.Where(Function(a) a.acl.Any())
or something closely resembling that (I'm not very well versed in VB.NET syntax).
I have a relatively simple LINQ expression which I need to convert into VB expression tree syntax. This is likely an easy task for folks that are familiar, but I am new to the realm of LINQ expression trees.
In my samples, you see a "New Int16() {}" array. That value must be parameterized at run-time with an array of values from another code element.
my query is:
from i in tblInstitutions
let ChildHasCategory = i.tblInstCtgyHistories.Where(Function(CtgyHist) CtgyHist.EndDate is Nothing AND ( (New Int16() {32,35,38,34}).Contains(CtgyHist.InstCtgyCodeFK)))
where ChildHasCategory.Any()
select i
Which can also be represented as:
tblInstitutions
.Select (i => new {
i = i,
ChildHasCategory = (IEnumerable<tblInstCtgyHistory>)(i.tblInstCtgyHistories)
.Where (
CtgyHist =>
((CtgyHist.EndDate == null) &
(IEnumerable<Int16>)(new Int16[] { 32, 35, 38, 34 } ).Contains (CtgyHist.InstCtgyCodeFK)
)
)
}
)
.Where ($VB$It => $VB$It.ChildHasCategory.Any ())
.Select ($VB$It => $VB$It.i)
This is going to be used in the context of a custom filter in an ASP.NET Dynamic Data web application. I'd like to mimic the default approach.
A sample of one of the other dynamic filter code-behind is:
Public Overrides Function GetQueryable(source As IQueryable) As IQueryable
Dim value = TextBox1.Text
If String.IsNullOrWhiteSpace(value) Then
Return source
End If
If DefaultValues IsNot Nothing Then
DefaultValues(Column.Name) = value
End If
Dim parameter = Expression.Parameter(source.ElementType)
Dim columnProperty = Expression.PropertyOrField(parameter, Column.Name)
Dim likeValue = Expression.Constant(value, GetType(String))
Dim condition = Expression.Call(columnProperty, GetType(String).GetMethod("Contains"), likeValue)
Dim where = Expression.Call(GetType(Queryable), "Where", New Type() {source.ElementType}, source.Expression, Expression.Lambda(condition, parameter))
Return source.Provider.CreateQuery(where)
End Function
I'm not sure you really need to worry about expression trees here. First off, we should be able to express your query as follows:
Dim targetCodes = new Int16() {32, 35, 38, 34 } ' This could be data driven as well
return from i in tblInstitutions
where i.tblInstCtgyHistories.Any(Function(ctgyHist) ctgyHist.EndDate is Nothing AndAlso
targetCodes.Contains(ctgyHist.InstCtgyCodeFK))
select i
Given that, under what case do you need the custom expression tree?
I added an Anonymous type to my project:
'Put the courses from the XML file in an Anonymous Type
Dim courses = From myCourse In xDoc.Descendants("Course")
Select New With
{
.StateCode = myCourse.Element("StateCode").Value, _
.Description = myCourse.Element("Description").Value, _
.ShortName = myCourse.Element("ShortName").Value, _
.LongName = myCourse.Element("LongName").Value, _
.Type = myCourse.Element("Type").Value, _
.CipCode = CType(myCourse.Element("CIPCode"), String) _
}
For Each course In courses
If Not UpdateSDECourseCode(acadYear, course.StateCode, course.Description, course.Type, course.ShortName, course.LongName, course.CipCode) Then errors.Add(String.Format("Cannot import State Course Number {0} with Year {1} ", course.StateCode, acadYear))
Next
After doing so, a Unit Test failed:
Public Function GetAreaTypeList() As List(Of Type)
Dim types As New List(Of Type)
Dim asmPath As String = IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "My.Stuff.dll")
For Each t As Type In Reflection.Assembly.LoadFrom(asmPath).GetTypes()
If t.Namespace.StartsWith("My.Stuff.BatchUpdater") Then
If t.BaseType Is GetType(My.Stuff.BatchUpdater.Area) Then
types.Add(t)
End If
End If
Next
Return types
End Function
It fails because a new type has been added to the project (VB$AnonymousType_0`6) and it does not have a property called Namespace.
I fixed by making the following change to the IF Statement:
If Not t.Namespace Is Nothing AndAlso t.Namespace.StartsWith("My.Stuff.BatchUpdater") Then
Since I don't fully understand what's happening, I feel leery about my code change.
Why is the Namespace Nothing for the Anonymous type?
Would you fix your Unit Test in the same fashion? Or should it be something more specific (e.g. If Not t.Names = "VB$AnonymousType_0`6")
UPDATE
decyclone gave me the info I needed to create a better test:
For Each t As Type In Reflection.Assembly.LoadFrom(asmPath).GetTypes()
'Ignore CompilerGeneratedAttributes (e.g. Anonymous Types)
Dim isCompilerGeneratedAttribute = t.GetCustomAttributes(False).Contains(New System.Runtime.CompilerServices.CompilerGeneratedAttribute())
If Not isCompilerGeneratedAttribute AndAlso t.Namespace.StartsWith("My.Stuff.BatchUpdater") Then
'...Do some things here
End If
Next
Honestly, it could be improved more with a LINQ query, but this suits me.
Anonymous methods and types are decorated with CompilerGeneratedAttribute. You can check for their existance to identify an anonymous type.
var anonymous = new { value = 1 };
Type anonymousType = anonymous.GetType();
var attributes = anonymousType.GetCustomAttributes(typeof(CompilerGeneratedAttribute), false);
if (attributes.Any())
{
// Anonymous
}
You can filter these out in your test.
It is also possible to mark a user defined type with CompilerGeneratedAttribute. So maybe you can combine it with checking if Namespace is null or not
var anonymous = new { value = 1 };
Type anonymousType = anonymous.GetType();
var attributes = anonymousType.GetCustomAttributes(typeof(CompilerGeneratedAttribute), false);
if (attributes.Any() && anonymousType.Namespace == null)
{
// Anonymous
}
I am dynamically creating a Lambda expression (based on user input but at the moment using dummy values for a proof-of-concept) for a type which I will only know at runtime. I therefore need to pass the T portion of the Func<T,TResult> as a dynamic type, since I won't know the type until runtime (TResult will always be a bool).
It seems that I cannot pass in a Type variable or use typeof with generics. Basically I'm trying to do something like this:
// (f => f.Baz == 1)
Type theType = Type.GetType("Foo");
ParameterExpression pe = Expression.Parameter(theType, "f");
Expression left = Expression.Property(pe, theType.GetProperty("Baz"));
Expression right = Expression.Constant(1);
Expression expr = Expression.Equal(left, right);
// This works fine but uses a hard-coded type, which I won't know until runtime:
// var lambda = Expression.Lambda<Func<Foo,bool>>(expr, new ParameterExpression[] { pe }).Compile();
var lambda = Expression.Lambda<Func<theType, bool>>(expr, new ParameterExpression[] { pe }).Compile();
However, I cannot use the variable theType as the T portion of the Func. How can I fix this?
No you can't.
For example, in C#, you can't:
Type t = typeof(int);
List<t> list = new List<t>();
or
object list = new List<t>();
Unless you use reflection, but then you have to put the list in an object, and you can use it only through reflection.
So if you want you can save your Func<> in an object (or a dynamic) but nothing more.
What you COULD do is always return Func<object, bool> and cast the object to the desidered type IN the lambda function (so use a Expression.Convert(pe, theType));
Or you could use the dynamic:
// lambda == Func<Foo, bool>
dynamic lamdba = Expression.Lambda(expr, new ParameterExpression[] { pe }).Compile();
bool res = lambda(myvalue);
or
// lambda == Func<Foo, bool>
Delegate lamdba = Expression.Lambda(expr, new ParameterExpression[] { pe }).Compile();
bool res = (bool)lambda2.DynamicInvoke(t);
To be taken "not as real" some benchmarks (in StopWatch.Ticks, look at them only for proportions) (Release Mode + Start Without Debugging + some useless cycles so that they are "hot"):
236384685 dynamic
56773593 Func<object, bool> + cast
10556024247 DynamicInvoke
as a note, Func<Foo, bool> has the same speed, so there isn't any speed lost in the extra cast.
You can see the code here http://ideone.com/qhnVP3
I'm getting this error from Moq via NUnit, and it doesn't make much in the way of sense to me.
"Expected invocation on the mock at least once, but was never performed: x => x.DeleteItem(.$VB$Local_item)"
"at Moq.Mock.ThrowVerifyException(MethodCall expected, IEnumerable1 setups, IEnumerable1 actualCalls, Expression expression, Times times, Int32 callCount)
at Moq.Mock.VerifyCalls(Interceptor targetInterceptor, MethodCall expected, Expression expression, Times times)
at Moq.Mock.Verify[T](Mock mock, Expression1 expression, Times times, String failMessage)
at Moq.Mock1.Verify(Expression`1 expression)
at PeekABookEditor.UnitTests.ItemBrowsing.Can_Delete_Item() in C:\Projects\MyProject\MyProject.UnitTests\Tests\ItemBrowsing.vb:line 167"
Very similar code works well in C#, so the error might be minor and syntactical on my part.
Here's my code:
<Test()> _
Public Sub Can_Delete_Item()
'Arrange: Given a repository containing some item...
Dim mockRepository = New Mock(Of IItemsRepository)()
Dim item As New Item With {.ItemID = "24", .Title = "i24"}
mockRepository.Setup(Function(x) x.Items).Returns(New Item() {item}.AsQueryable())
'Act ... when the user tries to delete that product
Dim controller = New ItemsController(mockRepository.Object)
Dim result = controller.Delete(24)
'Assert ... then it's deleted, and the user sees a confirmation
mockRepository.Verify(Sub(x) x.DeleteItem(item))
result.ShouldBeRedirectionTo(New With {Key .action = "List"})
Assert.AreEqual(DirectCast(controller.TempData("message"), String), "i24 was deleted")
End Sub
The guilty line appears to be "mockRepository.Verify(Sub(x) x.DeleteItem(item))"
Any thoughts on how to fix this?
Working C# code isn't the exact same, but here it is:
[Test]
public void Can_Delete_Product()
{
// Arrange: Given a repository containing some product...
var mockRepository = new Mock<IProductsRepository>();
var product = new Product { ProductID = 24, Name = "P24"};
mockRepository.Setup(x => x.Products).Returns(
new[] { product }.AsQueryable()
);
// Act: ... when the user tries to delete that product
var controller = new AdminController(mockRepository.Object);
var result = controller.Delete(24);
// Assert: ... then it's deleted, and the user sees a confirmation
mockRepository.Verify(x => x.DeleteProduct(product));
result.ShouldBeRedirectionTo(new { action = "Index" });
controller.TempData["message"].ShouldEqual("P24 was deleted");
}
In your VB test method, you create Item with a string ItemID = "24", but you call the controller.Delete method with an integer value of 24.
Check your controller code and see if the type discrepancy results in the item not being identified correctly, so either DeleteItem is not called at all, or is called with a different Item.