packages/Pester/Functions/It.ps1
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function It { <# .SYNOPSIS Validates the results of a test inside of a Describe block. .DESCRIPTION The It command is intended to be used inside of a Describe or Context Block. If you are familiar with the AAA pattern (Arrange-Act-Assert), the body of the It block is the appropriate location for an assert. The convention is to assert a single expectation for each It block. The code inside of the It block should throw a terminating error if the expectation of the test is not met and thus cause the test to fail. The name of the It block should expressively state the expectation of the test. In addition to using your own logic to test expectations and throw exceptions, you may also use Pester's Should command to perform assertions in plain language. .PARAMETER Name An expressive phrase describing the expected test outcome. .PARAMETER Test The script block that should throw an exception if the expectation of the test is not met.If you are following the AAA pattern (Arrange-Act-Assert), this typically holds the Assert. .PARAMETER Pending Use this parameter to explicitly mark the test as work-in-progress/not implemented/pending when you need to distinguish a test that fails because it is not finished yet from a tests that fail as a result of changes being made in the code base. An empty test, that is a test that contains nothing except whitespace or comments is marked as Pending by default. .PARAMETER Skip Use this parameter to explicitly mark the test to be skipped. This is preferable to temporarily commenting out a test, because the test remains listed in the output. Use the Strict parameter of Invoke-Pester to force all skipped tests to fail. .PARAMETER TestCases Optional array of hashtable (or any IDictionary) objects. If this parameter is used, Pester will call the test script block once for each table in the TestCases array, splatting the dictionary to the test script block as input. If you want the name of the test to appear differently for each test case, you can embed tokens into the Name parameter with the syntax 'Adds numbers <A> and <B>' (assuming you have keys named A and B in your TestCases hashtables.) .EXAMPLE function Add-Numbers($a, $b) { return $a + $b } Describe "Add-Numbers" { It "adds positive numbers" { $sum = Add-Numbers 2 3 $sum | Should Be 5 } It "adds negative numbers" { $sum = Add-Numbers (-2) (-2) $sum | Should Be (-4) } It "adds one negative number to positive number" { $sum = Add-Numbers (-2) 2 $sum | Should Be 0 } It "concatenates strings if given strings" { $sum = Add-Numbers two three $sum | Should Be "twothree" } } .EXAMPLE function Add-Numbers($a, $b) { return $a + $b } Describe "Add-Numbers" { $testCases = @( @{ a = 2; b = 3; expectedResult = 5 } @{ a = -2; b = -2; expectedResult = -4 } @{ a = -2; b = 2; expectedResult = 0 } @{ a = 'two'; b = 'three'; expectedResult = 'twothree' } ) It 'Correctly adds <a> and <b> to get <expectedResult>' -TestCases $testCases { param ($a, $b, $expectedResult) $sum = Add-Numbers $a $b $sum | Should Be $expectedResult } } .LINK Describe Context about_should #> [CmdletBinding(DefaultParameterSetName = 'Normal')] param( [Parameter(Mandatory = $true, Position = 0)] [string]$name, [Parameter(Position = 1)] [ScriptBlock] $test = {}, [System.Collections.IDictionary[]] $TestCases, [Parameter(ParameterSetName = 'Pending')] [Switch] $Pending, [Parameter(ParameterSetName = 'Skip')] [Alias('Ignore')] [Switch] $Skip ) ItImpl -Pester $pester -OutputScriptBlock ${function:Write-PesterResult} @PSBoundParameters } function ItImpl { [CmdletBinding(DefaultParameterSetName = 'Normal')] param( [Parameter(Mandatory = $true, Position=0)] [string]$name, [Parameter(Position = 1)] [ScriptBlock] $test, [System.Collections.IDictionary[]] $TestCases, [Parameter(ParameterSetName = 'Pending')] [Switch] $Pending, [Parameter(ParameterSetName = 'Skip')] [Alias('Ignore')] [Switch] $Skip, $Pester, [scriptblock] $OutputScriptBlock ) Assert-DescribeInProgress -CommandName It # Jumping through hoops to make strict mode happy. if ($PSCmdlet.ParameterSetName -ne 'Skip') { $Skip = $false } if ($PSCmdlet.ParameterSetName -ne 'Pending') { $Pending = $false } #unless Skip or Pending is specified you must specify a ScriptBlock to the Test parameter if (-not ($PSBoundParameters.ContainsKey('test') -or $Skip -or $Pending)) { throw 'No test script block is provided. (Have you put the open curly brace on the next line?)' } #the function is called with Pending or Skipped set the script block if needed if ($null -eq $test) { $test = {} } #mark empty Its as Pending #[String]::IsNullOrWhitespace is not available in .NET version used with PowerShell 2 if ($PSCmdlet.ParameterSetName -eq 'Normal' -and [String]::IsNullOrEmpty((Remove-Comments $test.ToString()) -replace "\s")) { $Pending = $true } $pendingSkip = @{} if ($PSCmdlet.ParameterSetName -eq 'Skip') { $pendingSkip['Skip'] = $Skip } else { $pendingSkip['Pending'] = $Pending } if ($null -ne $TestCases -and $TestCases.Count -gt 0) { foreach ($testCase in $TestCases) { $expandedName = [regex]::Replace($name, '<([^>]+)>', { $capture = $args[0].Groups[1].Value if ($testCase.Contains($capture)) { $testCase[$capture] } else { "<$capture>" } }) $splat = @{ Name = $expandedName Scriptblock = $test Parameters = $testCase ParameterizedSuiteName = $name OutputScriptBlock = $OutputScriptBlock } Invoke-Test @splat @pendingSkip } } else { Invoke-Test -Name $name -ScriptBlock $test @pendingSkip -OutputScriptBlock $OutputScriptBlock } } function Invoke-Test { [CmdletBinding(DefaultParameterSetName = 'Normal')] param ( [Parameter(Mandatory = $true)] [string] $Name, [Parameter(Mandatory = $true)] [ScriptBlock] $ScriptBlock, [scriptblock] $OutputScriptBlock, [System.Collections.IDictionary] $Parameters, [string] $ParameterizedSuiteName, [Parameter(ParameterSetName = 'Pending')] [Switch] $Pending, [Parameter(ParameterSetName = 'Skip')] [Alias('Ignore')] [Switch] $Skip ) if ($null -eq $Parameters) { $Parameters = @{} } try { if ($Skip) { $Pester.AddTestResult($Name, "Skipped", $null) } elseif ($Pending) { $Pester.AddTestResult($Name, "Pending", $null) } else { & $SafeCommands['Write-Progress'] -Activity "Running test '$Name'" -Status Processing $errorRecord = $null try { $pester.EnterTest() Invoke-TestCaseSetupBlocks do { $null = & $ScriptBlock @Parameters } until ($true) } catch { $errorRecord = $_ } finally { #guarantee that the teardown action will run and prevent it from failing the whole suite try { if (-not ($Skip -or $Pending)) { Invoke-TestCaseTeardownBlocks } } catch { $errorRecord = $_ } $pester.LeaveTest() } $result = ConvertTo-PesterResult -ErrorRecord $errorRecord $orderedParameters = Get-OrderedParameterDictionary -ScriptBlock $ScriptBlock -Dictionary $Parameters $Pester.AddTestResult( $result.name, $result.Result, $null, $result.FailureMessage, $result.StackTrace, $ParameterizedSuiteName, $orderedParameters, $result.ErrorRecord ) & $SafeCommands['Write-Progress'] -Activity "Running test '$Name'" -Completed -Status Processing } } finally { Exit-MockScope -ExitTestCaseOnly } if ($null -ne $OutputScriptBlock) { $Pester.testresult[-1] | & $OutputScriptBlock } } function Get-OrderedParameterDictionary { [OutputType([System.Collections.IDictionary])] param ( [scriptblock] $ScriptBlock, [System.Collections.IDictionary] $Dictionary ) $parameters = Get-ParameterDictionary -ScriptBlock $ScriptBlock $orderedDictionary = & $SafeCommands['New-Object'] System.Collections.Specialized.OrderedDictionary foreach ($parameterName in $parameters.Keys) { $value = $null if ($Dictionary.ContainsKey($parameterName)) { $value = $Dictionary[$parameterName] } $orderedDictionary[$parameterName] = $value } return $orderedDictionary } function Get-ParameterDictionary { param ( [scriptblock] $ScriptBlock ) $guid = [guid]::NewGuid().Guid try { & $SafeCommands['Set-Content'] function:\$guid $ScriptBlock $metadata = [System.Management.Automation.CommandMetadata](& $SafeCommands['Get-Command'] -Name $guid -CommandType Function) return $metadata.Parameters } finally { if (& $SafeCommands['Test-Path'] function:\$guid) { & $SafeCommands['Remove-Item'] function:\$guid } } } |