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c#msbuildmsbuild-taskinvalidoperationexception
David White
David White

Reputation: 3024

Unit test MSBuild Custom Task without "Task attempted to log before it was initialized" error

I have written a few MSBuild custom tasks that work well and are use in our CruiseControl.NET build process.

I am modifying one, and wish to unit test it by calling the Task's Execute() method.

However, if it encounters a line containing 

Log.LogMessage("some message here");

it throws an InvalidOperationException:

Task attempted to log before it was initialized. Message was...

Any suggestions? (In the past I have mostly unit-tested Internal static methods on my custom tasks to avoid such problems.)

Upvotes: 29

Views: 7928

Answers (6)

Jan Hlavsa
Jan Hlavsa

Reputation: 71

In assembly System.Web in namespace System.Web.Compilation is a class MockEngine which implements IBuildEngine interface in a way which describes Tim Murphy.

Upvotes: 0

Raymond Hallquist
Raymond Hallquist

Reputation: 41

I had the same problem. I solved it by stubbing the build engine. Like so (AppSettings is the MsBuild Task Name):

using Microsoft.Build.Framework;
using NUnit.Framework;
using Rhino.Mocks;

namespace NameSpace
{
    [TestFixture]
    public class Tests
    {
        [Test]
        public void Test()
        {
            MockRepository mock = new MockRepository();
            IBuildEngine engine = mock.Stub<IBuildEngine>();

            var appSettings = new AppSettings();
            appSettings.BuildEngine = engine;
            appSettings.Execute();
        }
    }
}

Upvotes: 4

Tim Murphy
Tim Murphy

Reputation: 4932

@Kiff comment on mock/stub IBuildEngine is a good idea. Here is my FakeBuildEngine. C# and VB.NET examples provided.

VB.NET

Imports System
Imports System.Collections.Generic
Imports Microsoft.Build.Framework

Public Class FakeBuildEngine
    Implements IBuildEngine

    // It's just a test helper so public fields is fine.
    Public LogErrorEvents As New List(Of BuildErrorEventArgs)
    Public LogMessageEvents As New List(Of BuildMessageEventArgs)
    Public LogCustomEvents As New List(Of CustomBuildEventArgs)
    Public LogWarningEvents As New List(Of BuildWarningEventArgs)

    Public Function BuildProjectFile(
        projectFileName As String, 
        targetNames() As String, 
        globalProperties As System.Collections.IDictionary, 
        targetOutputs As System.Collections.IDictionary) As Boolean
        Implements IBuildEngine.BuildProjectFile

        Throw New NotImplementedException

    End Function

    Public ReadOnly Property ColumnNumberOfTaskNode As Integer 
        Implements IBuildEngine.ColumnNumberOfTaskNode
        Get
            Return 0
        End Get
    End Property

    Public ReadOnly Property ContinueOnError As Boolean
        Implements IBuildEngine.ContinueOnError
        Get
            Throw New NotImplementedException
        End Get
    End Property

    Public ReadOnly Property LineNumberOfTaskNode As Integer
        Implements IBuildEngine.LineNumberOfTaskNode
        Get
            Return 0
        End Get
    End Property

    Public Sub LogCustomEvent(e As CustomBuildEventArgs)
        Implements IBuildEngine.LogCustomEvent
        LogCustomEvents.Add(e)
    End Sub

    Public Sub LogErrorEvent(e As BuildErrorEventArgs)
        Implements IBuildEngine.LogErrorEvent
        LogErrorEvents.Add(e)
    End Sub

    Public Sub LogMessageEvent(e As BuildMessageEventArgs)
        Implements IBuildEngine.LogMessageEvent
        LogMessageEvents.Add(e)
    End Sub

    Public Sub LogWarningEvent(e As BuildWarningEventArgs)
        Implements IBuildEngine.LogWarningEvent
        LogWarningEvents.Add(e)
    End Sub

    Public ReadOnly Property ProjectFileOfTaskNode As String
        Implements IBuildEngine.ProjectFileOfTaskNode
        Get
            Return "fake ProjectFileOfTaskNode"
        End Get
    End Property

End Class

C#

using System;
using System.Collections.Generic;
using Microsoft.Build.Framework;

public class FakeBuildEngine : IBuildEngine
{

    // It's just a test helper so public fields is fine.
    public List<BuildErrorEventArgs> LogErrorEvents = new List<BuildErrorEventArgs>();

    public List<BuildMessageEventArgs> LogMessageEvents = 
        new List<BuildMessageEventArgs>();

    public List<CustomBuildEventArgs> LogCustomEvents = 
        new List<CustomBuildEventArgs>();

    public List<BuildWarningEventArgs> LogWarningEvents =
        new List<BuildWarningEventArgs>();

    public bool BuildProjectFile(
        string projectFileName, string[] targetNames, 
        System.Collections.IDictionary globalProperties, 
        System.Collections.IDictionary targetOutputs)
    {
        throw new NotImplementedException();
    }

    public int ColumnNumberOfTaskNode
    {
        get { return 0; }
    }

    public bool ContinueOnError
    {
        get
        {
            throw new NotImplementedException();
        }
    }

    public int LineNumberOfTaskNode
    {
        get { return 0; }
    }

    public void LogCustomEvent(CustomBuildEventArgs e)
    {
        LogCustomEvents.Add(e);
    }

    public void LogErrorEvent(BuildErrorEventArgs e)
    {
        LogErrorEvents.Add(e);
    }

    public void LogMessageEvent(BuildMessageEventArgs e)
    {
        LogMessageEvents.Add(e);
    }

    public void LogWarningEvent(BuildWarningEventArgs e)
    {
        LogWarningEvents.Add(e);
    }

    public string ProjectFileOfTaskNode
    {
        get { return "fake ProjectFileOfTaskNode"; }
    }

}

Upvotes: 11

Branstar
Branstar

Reputation: 691

You need to set the .BuildEngine property of the custom task you are calling.

You can set it to the same BuildEngine your current task is using to include the output seamlessly.

Task myCustomTask = new CustomTask();
myCustomTask.BuildEngine = this.BuildEngine;
myCustomTask.Execute();

Upvotes: 27

Tim Bailey
Tim Bailey

Reputation: 571

I have found that the log instance does not work unless the task is running inside msbuild, so I usually wrap my calls to Log, then check the value of BuildEngine to determin if I am running inside msbuild. As below.

Tim

private void LogFormat(string message, params object[] args)
{
    if (this.BuildEngine != null)
    {
        this.Log.LogMessage(message, args);
    }
    else
    {
        Console.WriteLine(message, args);
    }
}

Upvotes: 15

evilhomer
evilhomer

Reputation: 9254

If you have implemented the interface ITask you will have to initialise the Log class yourself.

Otherwise you should just inherit from Task in Microsoft.Build.Utilities.dll That implements ITask and does a lot of the leg work for you.

Here is the reference page for building a custom task, it explains quite a lot of it.

Building a custom MSBuild task reference

Also worth a look is

How to debug a custom MSBuild task

Other then that could you post the MSBuild XML you are using for calling your custom task. The code itself would obviously be the most help :-)

Upvotes: 6

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