Invoke-Pester

SYNOPSIS

Runs Pester tests

SYNTAX

Default (Default)

Invoke-Pester [[-Script] <Object[]>] [[-TestName] <String[]>] [-EnableExit] [[-Tag] <String[]>]
[-ExcludeTag <String[]>] [-PassThru] [-CodeCoverage <Object[]>] [-CodeCoverageOutputFile <String>]
[-CodeCoverageOutputFileEncoding <String>] [-CodeCoverageOutputFileFormat <String>] [-Strict] [-Quiet]
[-PesterOption <Object>] [-Show <OutputTypes>] [<CommonParameters>]

NewOutputSet

Invoke-Pester [[-Script] <Object[]>] [[-TestName] <String[]>] [-EnableExit] [[-Tag] <String[]>]
[-ExcludeTag <String[]>] [-PassThru] [-CodeCoverage <Object[]>] [-CodeCoverageOutputFile <String>]
[-CodeCoverageOutputFileEncoding <String>] [-CodeCoverageOutputFileFormat <String>] [-Strict]
-OutputFile <String> [-OutputFormat <String>] [-Quiet] [-PesterOption <Object>] [-Show <OutputTypes>]
[<CommonParameters>]

DESCRIPTION

The Invoke-Pester function runs Pester tests, including *.Tests.ps1 files and Pester tests in PowerShell scripts.

You can run scripts that include Pester tests just as you would any other Windows PowerShell script, including typing the full path at the command line and running in a script editing program. Typically, you use Invoke-Pester to run all Pester tests in a directory, or to use its many helpful parameters, including parameters that generate custom objects or XML files.

By default, Invoke-Pester runs all *.Tests.ps1 files in the current directory and all subdirectories recursively. You can use its parameters to select tests by file name, test name, or tag.

To run Pester tests in scripts that take parameter values, use the Script parameter with a hash table value.

Also, by default, Pester tests write test results to the console host, much like Write-Host does, but you can use the Show parameter set to None to suppress the host messages, use the PassThru parameter to generate a custom object (PSCustomObject) that contains the test results, use the OutputXml and OutputFormat parameters to write the test results to an XML file, and use the EnableExit parameter to return an exit code that contains the number of failed tests.

You can also use the Strict parameter to fail all pending and skipped tests. This feature is ideal for build systems and other processes that require success on every test.

To help with test design, Invoke-Pester includes a CodeCoverage parameter that lists commands, classes, functions, and lines of code that did not run during test execution and returns the code that ran as a percentage of all tested code.

Invoke-Pester, and the Pester module that exports it, are products of an open-source project hosted on GitHub. To view, comment, or contribute to the repository, see https://github.com/Pester.

EXAMPLES

EXAMPLE 1

Invoke-Pester

This command runs all *.Tests.ps1 files in the current directory and its subdirectories.

EXAMPLE 2

Invoke-Pester -Script .\Util*

This commands runs all *.Tests.ps1 files in subdirectories with names that begin with 'Util' and their subdirectories.

EXAMPLE 3

Invoke-Pester -Script D:\MyModule, @{ Path = '.\Tests\Utility\ModuleUnit.Tests.ps1'; Parameters = @{ Name = 'User01' }; Arguments = srvNano16 }

This command runs all *.Tests.ps1 files in D:\MyModule and its subdirectories. It also runs the tests in the ModuleUnit.Tests.ps1 file using the following parameters: .\Tests\Utility\ModuleUnit.Tests.ps1 srvNano16 -Name User01

EXAMPLE 4

Invoke-Pester -Script @{Script = $scriptText}

This command runs all tests passed as string in $scriptText variable with no aditional parameters and arguments. This notation can be combined with Invoke-Pester -Script D:\MyModule, @{ Path = '.\Tests\Utility\ModuleUnit.Tests.ps1'; Parameters = @{ Name = 'User01' }; Arguments = srvNano16 } if needed. This command can be used when tests and scripts are stored not on the FileSystem, but somewhere else, and it is impossible to provide a path to it.

EXAMPLE 5

Invoke-Pester -TestName "Add Numbers"

This command runs only the tests in the Describe block named "Add Numbers".

EXAMPLE 6

$results = Invoke-Pester -Script D:\MyModule -PassThru -Show None
$failed = $results.TestResult | where Result -eq 'Failed'
$failed.Name
cannot find help for parameter: Force : in Compress-Archive
help for Force parameter in Compress-Archive has wrong Mandatory value
help for Compress-Archive has wrong parameter type for Force
help for Update parameter in Compress-Archive has wrong Mandatory value
help for DestinationPath parameter in Expand-Archive has wrong Mandatory value
$failed[0]
Describe : Test help for Compress-Archive in Microsoft.PowerShell.Archive (1.0.0.0)
Context : Test parameter help for Compress-Archive
Name : cannot find help for parameter: Force : in Compress-Archive
Result : Failed
Passed : False
Time : 00:00:00.0193083
FailureMessage : Expected: value to not be empty
StackTrace : at line: 279 in C:\GitHub\PesterTdd\Module.Help.Tests.ps1
279: $parameterHelp.Description.Text | Should Not BeNullOrEmpty
ErrorRecord : Expected: value to not be empty
ParameterizedSuiteName :
Parameters : {}

This examples uses the PassThru parameter to return a custom object with the Pester test results. By default, Invoke-Pester writes to the host program, but not to the output stream. It also uses the Show parameter set to None to suppress the host output.

The first command runs Invoke-Pester with the PassThru and Show parameters and saves the PassThru output in the $results variable.

The second command gets only failing results and saves them in the $failed variable.

The third command gets the names of the failing results. The result name is the name of the It block that contains the test.

The fourth command uses an array index to get the first failing result. The property values describe the test, the expected result, the actual result, and useful values, including a stack trace.

EXAMPLE 7

Invoke-Pester -EnableExit -OutputFile ".\artifacts\TestResults.xml" -OutputFormat NUnitXml

This command runs all tests in the current directory and its subdirectories. It writes the results to the TestResults.xml file using the NUnitXml schema. The test returns an exit code equal to the number of test failures.

EXAMPLE 8

Invoke-Pester -CodeCoverage 'ScriptUnderTest.ps1'

Runs all *.Tests.ps1 scripts in the current directory, and generates a coverage report for all commands in the "ScriptUnderTest.ps1" file.

EXAMPLE 9

Invoke-Pester -CodeCoverage @{ Path = 'ScriptUnderTest.ps1'; Function = 'FunctionUnderTest' }

Runs all *.Tests.ps1 scripts in the current directory, and generates a coverage report for all commands in the "FunctionUnderTest" function in the "ScriptUnderTest.ps1" file.

EXAMPLE 10

Invoke-Pester -CodeCoverage 'ScriptUnderTest.ps1' -CodeCoverageOutputFile '.\artifacts\TestOutput.xml'

Runs all *.Tests.ps1 scripts in the current directory, and generates a coverage report for all commands in the "ScriptUnderTest.ps1" file, and writes the coverage report to TestOutput.xml file using the JaCoCo XML Report DTD.

EXAMPLE 11

Invoke-Pester -CodeCoverage @{ Path = 'ScriptUnderTest.ps1'; StartLine = 10; EndLine = 20 }

Runs all *.Tests.ps1 scripts in the current directory, and generates a coverage report for all commands on lines 10 through 20 in the "ScriptUnderTest.ps1" file.

EXAMPLE 12

Invoke-Pester -Script C:\Tests -Tag UnitTest, Newest -ExcludeTag Bug

This command runs *.Tests.ps1 files in C:\Tests and its subdirectories. In those files, it runs only tests that have UnitTest or Newest tags, unless the test also has a Bug tag.

PARAMETERS

-Script

Specifies the test files that Pester runs. You can also use the Script parameter to pass parameter names and values to a script that contains Pester tests. The value of the Script parameter can be a string, a hash table, or a collection of hash tables and strings. Wildcard characters are supported.

The Script parameter is optional. If you omit it, Invoke-Pester runs all *.Tests.ps1 files in the local directory and its subdirectories recursively.

To run tests in other files, such as .ps1 files, enter the path and file name of the file. (The file name is required. Name patterns that end in ".ps1" run only .Tests.ps1 files.)

To run a Pester test with parameter names and/or values, use a hash table as the value of the script parameter. The keys in the hash table are:

-- Path string: Specifies a test to run. The value is a path\file name or name pattern. Wildcards are permitted. All hash tables in a Script parameter value must have a Path key.

-- Parameters [hashtable]: Runs the script with the specified parameters. The value is a nested hash table with parameter name and value pairs, such as @{UserName = 'User01'; Id = '28'}.

-- Arguments [array]: An array or comma-separated list of parameter values without names, such as 'User01', 28. Use this key to pass values to positional parameters.

Type: Object[]
Parameter Sets: (All)
Aliases: Path, relative_path
Required: False
Position: 1
Default value: .
Accept pipeline input: False
Accept wildcard characters: False

-TestName

Runs only tests in Describe blocks that have the specified name or name pattern. Wildcard characters are supported.

If you specify multiple TestName values, Invoke-Pester runs tests that have any of the values in the Describe name (it ORs the TestName values).

Type: String[]
Parameter Sets: (All)
Aliases: Name
Required: False
Position: 2
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-EnableExit

Will cause Invoke-Pester to exit with a exit code equal to the number of failed tests once all tests have been run. Use this to "fail" a build when any tests fail.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:
Required: False
Position: 3
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-Tag

Runs only tests in Describe blocks with the specified Tag parameter values. Wildcard characters are supported. Tag values that include spaces or whitespace will be split into multiple tags on the whitespace.

When you specify multiple Tag values, Invoke-Pester runs tests that have any of the listed tags (it ORs the tags). However, when you specify TestName and Tag values, Invoke-Pester runs only describe blocks that have one of the specified TestName values and one of the specified Tag values.

If you use both Tag and ExcludeTag, ExcludeTag takes precedence.

Type: String[]
Parameter Sets: (All)
Aliases: Tags
Required: False
Position: 5
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-ExcludeTag

Omits tests in Describe blocks with the specified Tag parameter values. Wildcard characters are supported. Tag values that include spaces or whitespace will be split into multiple tags on the whitespace.

When you specify multiple ExcludeTag values, Invoke-Pester omits tests that have any of the listed tags (it ORs the tags). However, when you specify TestName and ExcludeTag values, Invoke-Pester omits only describe blocks that have one of the specified TestName values and one of the specified Tag values.

If you use both Tag and ExcludeTag, ExcludeTag takes precedence

Type: String[]
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-PassThru

Returns a custom object (PSCustomObject) that contains the test results.

By default, Invoke-Pester writes to the host program, not to the output stream (stdout). If you try to save the result in a variable, the variable is empty unless you use the PassThru parameter.

To suppress the host output, use the Show parameter set to None.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-CodeCoverage

Adds a code coverage report to the Pester tests. Takes strings or hash table values.

A code coverage report lists the lines of code that did and did not run during a Pester test. This report does not tell whether code was tested; only whether the code ran during the test.

By default, the code coverage report is written to the host program (like Write-Host). When you use the PassThru parameter, the custom object that Invoke-Pester returns has an additional CodeCoverage property that contains a custom object with detailed results of the code coverage test, including lines hit, lines missed, and helpful statistics.

However, NUnitXml and JUnitXml output (OutputXML, OutputFormat) do not include any code coverage information, because it's not supported by the schema.

Enter the path to the files of code under test (not the test file). Wildcard characters are supported. If you omit the path, the default is local directory, not the directory specified by the Script parameter. Pester test files are by default excluded from code coverage when a directory is provided. When you provide a test file directly using string, code coverage will be measured. To include tests in code coverage of a directory, use the dictionary syntax and provide IncludeTests = $true option, as shown below.

To run a code coverage test only on selected classes, functions or lines in a script, enter a hash table value with the following keys:

-- Path (P)(mandatory) \<string>: Enter one path to the files. Wildcard characters are supported, but only one string is permitted. -- IncludeTests \<bool>: Includes code coverage for Pester test files (*.tests.ps1). Default is false.

One of the following: Class/Function or StartLine/EndLine

-- Class (C) \<string>: Enter the class name. Wildcard characters are supported, but only one string is permitted. Default is . -- Function (F) \<string>: Enter the function name. Wildcard characters are supported, but only one string is permitted. Default is .

-or-

-- StartLine (S): Performs code coverage analysis beginning with the specified line. Default is line 1. -- EndLine (E): Performs code coverage analysis ending with the specified line. Default is the last line of the script.

Type: Object[]
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: @()
Accept pipeline input: False
Accept wildcard characters: False

-CodeCoverageOutputFile

The path where Invoke-Pester will save formatted code coverage results file.

The path must include the location and name of the folder and file name with a required extension (usually the xml).

If this path is not provided, no file will be generated.

Type: String
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-CodeCoverageOutputFileEncoding

The encoding in which Invoke-Pester will save the code coverage results file as. Defaults to 'utf8'.

Supported encodings in the respective PowerShell version are the same as those supported by the cmdlet Out-File in that PowerShell version.

Type: String
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: Utf8
Accept pipeline input: False
Accept wildcard characters: False

-CodeCoverageOutputFileFormat

The name of a code coverage report file format.

Default value is: JaCoCo.

Currently supported formats are:

  • JaCoCo - this XML file format is compatible with the VSTS/TFS
Type: String
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: JaCoCo
Accept pipeline input: False
Accept wildcard characters: False

-Strict

Makes Pending and Skipped tests to Failed tests. Useful for continuous integration where you need to make sure all tests passed.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-OutputFile

The path where Invoke-Pester will save formatted test results log file.

The path must include the location and name of the folder and file name with the xml extension.

If this path is not provided, no log will be generated.

Type: String
Parameter Sets: NewOutputSet
Aliases:
Required: True
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-OutputFormat

The format of output. Two formats of output are supported: NUnitXml and JUnitXml.

Type: String
Parameter Sets: NewOutputSet
Aliases:
Required: False
Position: Named
Default value: NUnitXml
Accept pipeline input: False
Accept wildcard characters: False

-Quiet

The parameter Quiet is deprecated since Pester v. 4.0 and will be deleted in the next major version of Pester. Please use the parameter Show with value 'None' instead.

The parameter Quiet suppresses the output that Pester writes to the host program, including the result summary and CodeCoverage output.

This parameter does not affect the PassThru custom object or the XML output that is written when you use the Output parameters.

Type: SwitchParameter
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: False
Accept pipeline input: False
Accept wildcard characters: False

-PesterOption

Sets advanced options for the test execution. Enter a PesterOption object, such as one that you create by using the New-PesterOption cmdlet, or a hash table in which the keys are option names and the values are option values. For more information on the options available, see the help for New-PesterOption.

Type: Object
Parameter Sets: (All)
Aliases:
Required: False
Position: Named
Default value: None
Accept pipeline input: False
Accept wildcard characters: False

-Show

Customizes the output Pester writes to the screen. Available options are None, Default, Passed, Failed, Pending, Skipped, Inconclusive, Describe, Context, Summary, Header, All, Fails.

The options can be combined to define presets. Common use cases are:

None - to write no output to the screen. All - to write all available information (this is default option). Fails - to write everything except Passed (but including Describes etc.).

A common setting is also Failed, Summary, to write only failed tests and test summary.

This parameter does not affect the PassThru custom object or the XML output that is written when you use the Output parameters.

Type: OutputTypes
Parameter Sets: (All)
Aliases:
Accepted values: None, Default, Passed, Failed, Pending, Skipped, Inconclusive, Describe, Context, Summary, Header, Fails, All
Required: False
Position: Named
Default value: All
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/commands/New-PesterOption