Describe

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SYNOPSIS

Creates a logical group of tests.

SYNTAX

Describe [-Name] <String> [-Tag <String[]>] [[-Fixture] <ScriptBlock>] [-Skip] [-AllowNullOrEmptyForEach]
 [-ForEach <Object>] [<CommonParameters>]

DESCRIPTION

Creates a logical group of tests. All Mocks, TestDrive and TestRegistry contents defined within a Describe block are scoped to that Describe; they will no longer be present when the Describe block exits. A Describe block may contain any number of Context and It blocks.

EXAMPLES

EXAMPLE 1

BeforeAll {
    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"
    }
}

Using Describe to group tests logically at the root of the script/container

PARAMETERS

-Name

The name of the test group. This is often an expressive phrase describing the scenario being tested.

Type: String
Parameter Sets: (All)
Aliases:

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

-Tag

Optional parameter containing an array of strings. When calling Invoke-Pester, it is possible to specify a -Tag parameter which will only execute Describe blocks containing the same Tag.

Type: String[]
Parameter Sets: (All)
Aliases: Tags

Required: False
Position: Named
Default value: @()
Accept pipeline input: False
Accept wildcard characters: False

-Fixture

The actual test script. If you are following the AAA pattern (Arrange-Act-Assert), this typically holds the arrange and act sections. The Asserts will also lie in this block but are typically nested each in its own It block. Assertions are typically performed by the Should command within the It blocks.

Type: ScriptBlock
Parameter Sets: (All)
Aliases:

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

-Skip

Use this parameter to explicitly mark the block to be skipped. This is preferable to temporarily commenting out a block, because it remains listed in the output.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:

Required: False
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-AllowNullOrEmptyForEach

Allows empty or null values for -ForEach when Run.FailOnNullOrEmptyForEach is enabled. This might be excepted in certain scenarios like using external data.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:

Required: False
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-ForEach

Allows data driven tests to be written. Takes an array of data and generates one block for each item in the array, and makes the item available as $_ in all child blocks. When the array is an array of hashtables, it additionally defines each key in the hashtable as variable.

Type: Object
Parameter Sets: (All)
Aliases:

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

CommonParameters

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

INPUTS

OUTPUTS

NOTES

RELATED LINKS

https://pester.dev/docs/commands/Describe

https://pester.dev/docs/usage/test-file-structure

https://pester.dev/docs/usage/mocking

https://pester.dev/docs/usage/testdrive

VERSION

This page was generated using comment-based help in Pester 6.0.0-alpha5.