Powershell Assertion Framework

# Based upon: http://www.leeholmes.com/blog/2005/09/05/unit-testing-in-powershell-%E2%80%93-a-link-parser/
# Updated to Powershell 2

Set-StrictMode -Version Latest

## A simple assert function.  Verifies that $condition
## is true.  If not, outputs the specified error message.
function assert
[bool] $condition,
[string] $message = “Test failed.”

if(-not $condition)
write-host “FAIL. $message”
write-host -NoNewLine “.”

## A simple “assert equals” function.  Verifies that $expected
## is equal to $actual.  If not, outputs the specified error message.
function assertEquals
[string] $message = “Test failed.”

if(-not ($expected -eq $actual))
write-host “FAIL.  Expected: ‘$expected’.  Actual: ‘$actual’.  $message.”
write-host -NoNewLine “.”;

Simple MEF Example

using System;
using System.ComponentModel.

Composition; // This is the assembly
using System.ComponentModel.Composition.Hosting;
using System.Reflection;

namespace SimpleMEF
public class Class1
static void Main()
AssemblyCatalog catalog = new AssemblyCatalog(Assembly.GetExecutingAssembly());
CompositionContainer container = new CompositionContainer(catalog);

User user = new User();

class User
private IExecute execute;

public void Start()

public interface IExecute
string Execute();

class First : IExecute

public string Execute()
return “First”;

Useful powershell about_ commands

powershells get-help system is wonderful (not quite sure about the new update-help).

Here are some useful get-help topics:

about_Aliases                     HelpFile                            Describes how to use alternate names for cmdlets and commands in Windows
about_Arithmetic_Operators        HelpFile                            Describes the operators that perform arithmetic in Windows PowerShell.
about_Arrays                      HelpFile                            SHORT DESCRIPTION
about_Assignment_Operators        HelpFile                            Describes how to use operators to assign values to variables.
about_Automatic_Variables         HelpFile                            Describes variables that store state information for Windows PowerShell.
about_Break                       HelpFile                            Describes a statement you can use to immediately exit Foreach, For, While,
about_Command_Precedence          HelpFile                            Describes how Windows PowerShell determines which command to run.
about_Command_Syntax              HelpFile                            Describes the syntax diagrams that are used in Windows PowerShell.
about_Comment_Based_Help          HelpFile                            SHORT DESCRIPTION
about_CommonParameters            HelpFile                            SHORT DESCRIPTION
about_Comparison_Operators        HelpFile                            SHORT DESCRIPTION
about_Continue                    HelpFile                            Describes how the Continue statement immediately returns the program flow
about_Core_Commands               HelpFile                            Lists the cmdlets that are designed for use with Windows PowerShell
about_Data_Sections               HelpFile                            Explains Data sections, which isolate text strings and other read-only
about_Debuggers                   HelpFile                            Describes the Windows PowerShell debugger.
about_Do                          HelpFile                            Runs a statement list one or more times, subject to a While or Until
about_Environment_Variables       HelpFile                            Describes how to access Windows environment variables in Windows
about_Escape_Characters           HelpFile                            Introduces the escape character in Windows PowerShell and explains
about_Eventlogs                   HelpFile                            Windows PowerShell creates a Windows event log that is
about_Execution_Policies          HelpFile                            Describes the Windows PowerShell execution policies and explains
about_For                         HelpFile                            SHORT DESCRIPTION
about_Foreach                     HelpFile                            Describes a language command you can use to traverse all the items in a
about_Format.ps1xml               HelpFile                            The Format.ps1xml files in Windows PowerShell define the default display
about_Functions                   HelpFile                            Describes how to create and use functions in Windows PowerShell.
about_Functions_Advanced          HelpFile                            Introduces advanced functions that act similar to cmdlets.
about_Functions_Advanced_Methods  HelpFile                            Describes how functions that specify the CmdletBinding attribute can use
about_Functions_Advanced_Param… HelpFile                            Explains how to add parameters to advanced functions.
about_Functions_CmdletBindingA… HelpFile                            Describes the attribute that makes a function work like a
about_Functions_OutputTypeAttr… HelpFile                            SHORT DESCRIPTION
about_Group_Policy_Settings       HelpFile                            Describes the Group Policy settings for Windows PowerShell
about_Hash_Tables                 HelpFile                            SHORT DESCRIPTION
about_History                     HelpFile                            Describes how to get and run commands in the command history.
about_If                          HelpFile                            Describes a language command you can use to run statement lists based
about_Jobs                        HelpFile                            Provides information about how Windows PowerShell background jobs run a
about_Job_Details                 HelpFile                            SHORT DESCRIPTION
about_Join                        HelpFile                            SHORT DESCRIPTION
about_Language_Keywords           HelpFile                            SHORT DESCRIPTION
about_Line_Editing                HelpFile                            Describes how to edit commands at the Windows PowerShell command prompt.
about_Locations                   HelpFile                            Describes how to access items from the working location in Windows
about_Logical_Operators           HelpFile                            Describes the operators that connect statements in Windows PowerShell.
about_Methods                     HelpFile                            Describes how to use methods to perform actions on objects in Windows
about_Modules                     HelpFile                            Explains how to install, import, and use Windows PowerShell modules.
about_Objects                     HelpFile                            SHORT DESCRIPTION
about_Object_Creation             HelpFile                            SHORT DESCRIPTION
about_Operators                   HelpFile                            Describes the operators that are supported by Windows PowerShell.
about_Operator_Precedence         HelpFile                            Lists the Windows PowerShell operators in precedence order.
about_Parameters                  HelpFile                            SHORT DESCRIPTION
about_Parameters_Default_Values   HelpFile                            SHORT DESCRIPTION
about_Parsing                     HelpFile                            Describes how Windows PowerShell parses commands.
about_Path_Syntax                 HelpFile                            Describes the full and relative path name formats in Windows PowerShell.
about_Pipelines                   HelpFile                            Combining commands into pipelines in the Windows PowerShell
about_PowerShell.exe              HelpFile                            Explains how to use the PowerShell.exe command-line tool. Displays
about_PowerShell_Ise.exe          HelpFile                            Explains how to use the PowerShell_Ise.exe command-line tool.
about_Preference_Variables        HelpFile                            Variables that customize the behavior of Windows PowerShell
about_Profiles                    HelpFile                            Describes how to create and use a Windows PowerShell profile.
about_Prompts                     HelpFile                            SHORT DESCRIPTION
about_Properties                  HelpFile                            Describes how to use object properties in Windows PowerShell.
about_Providers                   HelpFile                            Describes how Windows PowerShell providers provide access to data and
about_PSSessions                  HelpFile                            Describes Windows PowerShell sessions (PSSessions) and explains how to
about_PSSession_Details           HelpFile                            Provides detailed information about Windows PowerShell sessions and the
about_PSSnapins                   HelpFile                            Describes Windows PowerShell snap-ins and shows how to use and manage them.
about_Quoting_Rules               HelpFile                            SHORT DESCRIPTION
about_Redirection                 HelpFile                            Explains how to redirect output from Windows PowerShell to text files.
about_Ref                         HelpFile                            Describes how to create and use a reference variable type.
about_Regular_Expressions         HelpFile                            Describes regular expressions in Windows PowerShell.
about_Remote                      HelpFile                            Describes how to run remote commands in Windows PowerShell.
about_Remote_Disconnected_Sess… HelpFile                            Explains how to disconnect from and reconnect to a PSSession
about_Remote_FAQ                  HelpFile                            Contains questions and answers about running remote commands
about_Remote_Jobs                 HelpFile                            Describes how to run background jobs on remote computers.
about_Remote_Output               HelpFile                            Describes how to interpret and format the output of remote commands.
about_Remote_Requirements         HelpFile                            Describes the system requirements and configuration requirements for
about_Remote_Troubleshooting      HelpFile                            Describes how to troubleshoot remote operations in Windows PowerShell.
about_Remote_Variables            HelpFile                            Explains how to use local and remote variables in remote
about_Requires                    HelpFile                            Prevents a script from running without the required elements.
about_Reserved_Words              HelpFile                            Lists the reserved words that cannot be used as identifiers because they
about_Return                      HelpFile                            Exits the current scope, which can be a function, script, or script block.
about_Run_With_PowerShell         HelpFile                            Explains how to use the “Run with PowerShell” feature to run
about_Scopes                      HelpFile                            Explains the concept of scope in Windows PowerShell and shows how to set
about_Scripts                     HelpFile                            Describes how to run and write scripts in Windows PowerShell.
about_Script_Blocks               HelpFile                            Defines what a script block is and explains how to use script blocks in
about_Script_Internationalization HelpFile                            Describes the script internationalization features of Windows PowerShell 2.0
about_Session_Configurations      HelpFile                            Describes session configurations, which determine the users who can
about_Session_Configuration_Files HelpFile                            Describes session configuration files, which can be used in a
about_Signing                     HelpFile                            SHORT DESCRIPTION
about_Special_Characters          HelpFile                            Describes the special characters that you can use to control how
about_Splatting                   HelpFile                            SHORT DESCRIPTION
about_Split                       HelpFile                            Explains how to use the Split operator to split one or more strings into
about_Switch                      HelpFile                            SHORT DESCRIPTION
about_Throw                       HelpFile                            Describes the Throw keyword, which generates a terminating error.
about_Transactions                HelpFile                            Describes how to manage transacted operations in Windows PowerShell.
about_Trap                        HelpFile                            Describes a keyword that handles a terminating error.
about_Try_Catch_Finally           HelpFile                            Describes how to use the Try, Catch, and Finally blocks to handle
about_Types.ps1xml                HelpFile                            Explains how to use Types.ps1xml files to extend the types of objects
about_Type_Operators              HelpFile                            Describes the operators that work with Microsoft .NET Framework types.
about_Updatable_Help              HelpFile                            SHORT DESCRIPTION
about_Variables                   HelpFile                            Describes how variables store values that can be used in Windows
about_While                       HelpFile                            Describes a language statement that you can use to run a command block
about_Wildcards                   HelpFile                            Describes how to use wildcard characters in Windows PowerShell.
about_Windows_PowerShell_3.0      HelpFile                            Describes some of the new features that are included in
about_Windows_PowerShell_ISE      HelpFile                            SHORT DESCRIPTION
about_WMI                         HelpFile                            SHORT DESCRIPTION
about_Wmi_Cmdlets                 HelpFile                            Provides background information about Windows Management Instrumentation
about_WQL                         HelpFile                            SHORT DESCRIPTION
about_WS-Management_Cmdlets       HelpFile                            Provides an overview of Web Services for Management (WS-Management) as