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Version: v4



A step in a test, also known as a Given, When, or Then


GherkinStep [-Name] <String> [-Test] <ScriptBlock> [<CommonParameters>]


Pester doesn't technically distinguish between the three kinds of steps. However, we strongly recommend that you do! These words were carefully selected to convey meaning which is crucial to get you into the BDD mindset.

In BDD, we drive development by not first stating the requirements, and then defining steps which can be executed in a manner that is similar to unit tests.



# Gherkin Steps need to be placed in a *.Step.ps1 file

# filename: copyfile.Step.ps1

Given 'we have a destination folder' {
mkdir testdrive:\target -ErrorAction SilentlyContinue
'testdrive:\target' | Should -Exist

When 'we call Copy-Item' {
{ Copy-Item testdrive:\source\something.txt testdrive:\target } | Should -Not -Throw

Then 'we have a new file in the destination' {
'testdrive:\target\something.txt' | Should -Exist

# Steps need to allign with feature specifications in a *.feature file

# filename: copyfile.feature
Feature: You can copy one file

Scenario: The file exists, and the target folder exists
Given we have a source file
And we have a destination folder
When we call Copy-Item
Then we have a new file in the destination
And the new file is the same as the original file


# This example shows a complex regex match that can be used for multiple lines in the feature specification

# The named match is mapped to the script parameter

# filename: namedregex.Step.ps1

Given 'we have a (?\<name\>\S*) function' {
"$psscriptroot\..\MyModule\*\$name.ps1" | Should -Exist

# filename: namedregex.feature

Scenario: basic feature support
Given we have public functions
And we have a New-Node function
And we have a New-Edge function
And we have a New-Graph function
And we have a New-Subgraph function



The name of a gherkin step is actually a regular expression, from which capturing groups are cast and passed to the parameters in the ScriptBlock

Type: String
Parameter Sets: (All)

Required: True
Position: 1
Default value: None
Accept pipeline input: False
Accept wildcard characters: False


The ScriptBlock which defines this step. May accept parameters from regular expression capturing groups (named or not), or from tables or multiline strings.

Type: ScriptBlock
Parameter Sets: (All)

Required: True
Position: 2
Default value: None
Accept pipeline input: False
Accept wildcard characters: False


This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable, -InformationAction, -InformationVariable, -OutVariable, -OutBuffer, -PipelineVariable, -Verbose, -WarningAction, and -WarningVariable. For more information, see about_CommonParameters.





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