Assert-That.ps1
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# Copyright 2012 - 2015 Aaron Jensen # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. function Assert-That { <# .SYNOPSIS Asserts that an object meets certain conditions and throws an exception when they aren't. .DESCRIPTION The `Assert-That` function checks that a given set of condiions are true and if they aren't, it throws a `Blade.AssertionException`. .EXAMPLE Assert-That { throw 'Fubar!' } -Throws [Management.Automation.RuntimeException] Demonstrates how to check that a script block throws an exception. .EXAMPLE Assert-That { } -DoesNotThrowException Demonstrates how to check that a script block doesn't throw an exception. #> [CmdletBinding()] param( [Parameter(Mandatory=$true,Position=0)] [object] # The object whose conditions you're checking. $InputObject, [Parameter(Mandatory=$true,ParameterSetName='ThrowsException')] [Type] # The type of the exception `$InputObject` should throw. When this parameter is provided, $INputObject should be a script block. $Throws, [Parameter(ParameterSetName='ThrowsException')] [string] # Used with the `Throws` switch. Checks that the thrown exception message matches a regular rexpression. $AndMessageMatches, [Parameter(Mandatory=$true,ParameterSetName='DoesNotThrowException')] [Switch] # Asserts that the script block given by `InputObject` does not throw an exception. $DoesNotThrowException, [Parameter(ParameterSetName='ThrowsException',Position=1)] [string] # The message to show when the assertion fails. $Message ) Set-StrictMode -Version 'Latest' switch( $PSCmdlet.ParameterSetName ) { 'DoesNotThrowException' { if( $InputObject -isnot [scriptblock] ) { throw 'When using `DoesNotThrowException` parameter, `-InputObject` must be a ScriptBlock.' } try { Invoke-Command -ScriptBlock $InputObject } catch { Fail ('Script block threw an exception: {0} {1}' -f $_.Exception,$Message) } } 'ThrowsException' { if( $InputObject -isnot [scriptblock] ) { throw 'When using `Throws` parameter, `-InputObject` must be a ScriptBlock.' } $threwException = $false $ex = $null try { Invoke-Command -ScriptBlock $InputObject } catch { $ex = $_.Exception if( $ex -is $Throws ) { $threwException = $true } else { Fail ('Expected ScriptBlock to throw a {0} exception, but it threw: {1} {2}' -f $Throws,$ex,$Message) } } if( -not $threwException ) { Fail ('ScriptBlock did not throw a ''{0}'' exception. {1}' -f $Throws.FullName,$Message) } if( $AndMessageMatches ) { if( $ex.Message -notmatch $AndMessageMatches ) { Fail ('Exception message ''{0}'' doesn''t match ''{1}''.' -f $ex.Message,$AndMessageMatches) } } } } } |