Class AllocatingGCMemoryConstraint

An NUnit test constraint class to test whether a given block of code makes any GC allocations.

Use this class with NUnit's Assert.That() method to make assertions about the GC behaviour of your code. The constraint executes the delegate you provide, and checks if it has caused any GC memory to be allocated. If any GC memory was allocated, the constraint passes; otherwise, the constraint fails.

Usually you negate this constraint to make sure that your delegate does not allocate any GC memory. This is easy to do using the Is class:

Inheritance

object

Constraint

AllocatingGCMemoryConstraint

Implements

IConstraint

IResolveConstraint

Inherited Members

Constraint.ApplyTo<TActual>(ref TActual)

Constraint.GetTestObject<TActual>(ActualValueDelegate<TActual>)

Constraint.ToString()

Constraint.GetStringRepresentation()

Constraint.After(int)

Constraint.After(int, int)

Constraint.DisplayName

Constraint.Arguments

Constraint.Builder

Constraint.And

Constraint.With

Constraint.Or

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

Namespace: UnityEngine.TestTools.Constraints

Assembly: UnityEngine.TestRunner.dll

Syntax

public class AllocatingGCMemoryConstraint : Constraint, IConstraint, IResolveConstraint

Examples

using NUnit.Framework;
using UnityEngine.TestTools.Constraints;
using Is = UnityEngine.TestTools.Constraints.Is;

public class MyTestClass
{
    [Test]
    public void SettingAVariableDoesNotAllocate()
    {
        Assert.That(() => {
            int a = 0;
            a = 1;
        }, Is.Not.AllocatingGCMemory());
    }
}

Properties

Description

The Description of what this constraint tests, for to use in messages and in the ConstraintResult.

Declaration

public override string Description { get; }

Property Value

Type	Description
string

Overrides

NUnit.Framework.Constraints.Constraint.Description

Methods

ApplyTo(object)

Applies GC memory constraint to the test.

Declaration

public override ConstraintResult ApplyTo(object obj)

Parameters

Type	Name	Description
object	obj	An object to apply the GC constraint to. Should be a NUnit.Framework.TestDelegate.

Returns

Type	Description
ConstraintResult	A ConstraintResult

Overrides

Constraint.ApplyTo(object)

Exceptions

Type	Condition
ArgumentNullException	Throws a ArgumentNullException if the provided object is null.
ArgumentException	Throws a ArgumentException if the provided object is not a NUnit.Framework.TestDelegate.

ApplyTo<TActual>(ActualValueDelegate<TActual>)

Test whether the constraint is satisfied by a given reference. The default implementation simply dereferences the value but derived classes may override it to provide for delayed processing.

Declaration

public override ConstraintResult ApplyTo<TActual>(ActualValueDelegate<TActual> del)

Parameters

Type	Name	Description
ActualValueDelegate<TActual>	del	A reference to the value delegate to be tested

Returns

Type	Description
ConstraintResult	A ConstraintResult

Type Parameters

Name	Description
TActual	The type of the actual value delegate to be tested.

Overrides

NUnit.Framework.Constraints.Constraint.ApplyTo<TActual>(NUnit.Framework.Constraints.ActualValueDelegate<TActual>)

Exceptions

Type	Condition
ArgumentNullException	Throws a ArgumentNullException if the provided delegate is null.

Implements

NUnit.Framework.Constraints.IConstraint

NUnit.Framework.Constraints.IResolveConstraint