BeforeEach and AfterEach

Description

The BeforeEach and AfterEach commands allow you to define setup and teardown tasks that are performed at the beginning and end of every It block. This can eliminate duplication of code in test scripts, ensure that each test is performed on a pristine state regardless of their order, and perform any necessary cleanup tasks after each test.

BeforeEach and AfterEach blocks may be defined inside of any Describe or Context. If they are present in both a Context and its parent Describe, BeforeEach blocks in the Describe scope are executed first, followed by BeforeEach blocks in the Context scope. AfterEach blocks are the reverse of this, with the Context AfterEach blocks executing before Describe.

The script blocks assigned to BeforeEach and AfterEach are dot-sourced in the Context or Describe which contains the current It statement, so you don't have to worry about the scope of variable assignments. Any variables that are assigned values within a BeforeEach block can be used inside the body of the It block.

Note about syntax and placement

Unlike most of the commands in a Pester script, BeforeEach and AfterEach blocks apply to the entire Describe or Context scope in which they are defined, regardless of the order of commands inside the Describe or Context. In other words, even if an It block appears before BeforeEach or AfterEach in the tests file, the BeforeEach and AfterEach will still be executed.

Example

Describe 'Testing BeforeEach and AfterEach' {
    $afterEachVariable = 'AfterEach has not been executed yet'

    It 'Demonstrates that BeforeEach may be defined after the It command' {
        $beforeEachVariable | Should -Be 'Set in a describe-scoped BeforeEach'
        $afterEachVariable | Should -Be 'AfterEach has not been executed yet'
    }

    It 'Demonstrates that AfterEach has executed after the end of the first test' {
        $afterEachVariable | Should -Be 'AfterEach has been executed'
    }

    BeforeEach {
        $beforeEachVariable = 'Set in a describe-scoped BeforeEach'
    }

    AfterEach {
        $afterEachVariable = 'AfterEach has been executed'
    }
}