Share data among tests safely

sharing-test-data.ps1

# GOOD:
# shares data among tests without polluting 
# the script scope
Describe "I share data" { 

    $container = @{ Value = 1 }

    It "I give data" {
        $container.Value = 5
    }

    It "I get data" {
        $container.Value | Should -Be 5
    }
}

Describe "I don't want any data" {
    It "does not get data from the previous describe" {
        $container.Value | Should -Be $null
    }
}

# BAD: 
# shares data witih the describe but
# also leaks it to all other tests
Describe "I share data" { 

    $script:value = 1

    It "I give data" {
        $script:value = 5
    }

    It "I get data" {
        $script:value | Should -Be 5
    }
}


Describe "I don't want any data" {
    It "does not get data from the previous describe" {
        # yikes, data leaked here making this test fail
        $script:value | Should -Be $null
    }
}