ExpectedExceptionAttribute Class

Article
03/28/2012

Indicates that an exception is expected during test method execution. This class cannot be inherited.

Inheritance Hierarchy

System.Object
  System.Attribute
    Microsoft.VisualStudio.TestTools.UnitTesting.ExpectedExceptionBaseAttribute
      Microsoft.VisualStudio.TestTools.UnitTesting.ExpectedExceptionAttribute

Namespace: Microsoft.VisualStudio.TestTools.UnitTesting
Assembly: Microsoft.VisualStudio.QualityTools.UnitTestFramework (in Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll)

Syntax

'Declaration
<AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple := False, Inherited := True)> _
Public NotInheritable Class ExpectedExceptionAttribute _
    Inherits ExpectedExceptionBaseAttribute

[AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public sealed class ExpectedExceptionAttribute : ExpectedExceptionBaseAttribute

[AttributeUsageAttribute(AttributeTargets::Method, AllowMultiple = false, Inherited = true)]
public ref class ExpectedExceptionAttribute sealed : public ExpectedExceptionBaseAttribute

[<Sealed>]
[<AttributeUsageAttribute(AttributeTargets.Method, AllowMultiple = false, Inherited = true)>]
type ExpectedExceptionAttribute =  
    class
        inherit ExpectedExceptionBaseAttribute
    end

public final class ExpectedExceptionAttribute extends ExpectedExceptionBaseAttribute

The ExpectedExceptionAttribute type exposes the following members.

Constructors

	Name	Description
	ExpectedExceptionAttribute(Type)	Initializes a new instance of the ExpectedExceptionAttribute class with an expected exception.
	ExpectedExceptionAttribute(Type, String)	Initializes a new instance of the ExpectedExceptionAttribute class with and expected exception type and a message that describes the exception.

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Properties

	Name	Description
	AllowDerivedTypes
	ExceptionType	Gets the expected exception type.
	NoExceptionMessage	Infrastructure. (Inherited from ExpectedExceptionBaseAttribute.)
	TestContext	Infrastructure. (Inherited from ExpectedExceptionBaseAttribute.)
	TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)

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Methods

	Name	Description
	Equals	Infrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Returns the hash code for this instance. (Inherited from Attribute.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	IsDefaultAttribute	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
	Match	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	RethrowIfAssertException	Throws the exception again if it is an AssertFailedException or an AssertInconclusiveException. (Inherited from ExpectedExceptionBaseAttribute.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)
	Verify	Infrastructure. (Inherited from ExpectedExceptionBaseAttribute.)

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Explicit Interface Implementations

	Name	Description
	_Attribute.GetIDsOfNames	Maps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
	_Attribute.GetTypeInfo	Retrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
	_Attribute.GetTypeInfoCount	Retrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
	_Attribute.Invoke	Provides access to properties and methods exposed by an object. (Inherited from Attribute.)

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Remarks

This attribute is used to test whether an expected exception is thrown. The test method will pass if the expected exception is thrown. The test will fail if the thrown exception inherits from the expected exception.

If a test has both an ExpectedException attribute and an Assert statement, either one can cause the test to fail. To determine whether the attribute or the statement caused the test to fail, double-click the test result to open the Results Details page for the test. For more information about test results, see Test Results Reported.

This attribute can be specified on a method. There can be only one instance of this attribute on a method.

For more information about how to use attributes, see Extending Metadata Using Attributes.

Examples

The following class contains the method to test:

using System;

namespace MyCSNamespace
{
    public class DivisionClass
    {
        public int Divide(int numerator, int denominator)
        {
            return numerator / denominator;
        }
    }
}

Public Class DivisionClass
   Public Function Divide(ByVal numerator As Integer, ByVal denominator As Integer) As Integer
      Return numerator \ denominator
   End Function
End Class

The following test method tests the Divide method of the DivisionClass object. It tests for the existence of a DivideByZeroException.

using Microsoft.VisualStudio.TestTools.UnitTesting;
using MyCSNamespace;

namespace MyCSTestProject
{
    [TestClass()]
    public class DivisionClassTest
    {
        [TestMethod()]
        [ExpectedException(typeof(System.DivideByZeroException))]
        public void DivideTest()
        {
            DivisionClass target = new DivisionClass();
            int numerator = 4;
            int denominator = 0;
            int actual;
            actual = target.Divide(numerator, denominator);
        }
    }
}

Imports Microsoft.VisualStudio.TestTools.UnitTesting
Imports MyVBProject

<TestClass()> _
Public Class DivisionClassTest
    <TestMethod()> _
    <ExpectedException(GetType(System.DivideByZeroException), "MyMessage")> _
    Public Sub DivideTest()
        Dim target As DivisionClass = New DivisionClass
        Dim numerator As Integer = 4
        Dim denominator As Integer = 0
        Dim actual As Integer
        actual = target.Divide(numerator, denominator)
    End Sub
End Class

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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