. $PSScriptRoot\..\..\Load-PesterModules.ps1
$here = Split-Path -Parent $MyInvocation.MyCommand.Path
$sut = (Split-Path -Leaf $MyInvocation.MyCommand.Path) -replace '\.tests\.', '.'
$functionPath = Join-Path -Path $here -ChildPath $sut
Write-Host "Overriding SUT: $functionPath"
Import-Module $functionPath -Force
$moduleForMock = ""

Describe "Get-HostnamesByEnvironmentName" {

    # Load up AWSPowerShell for Mocking if Available
    $awsPowerShellLoaded = $false
    if ($null -ne (Get-Module -ListAvailable AWSPowerShell)) {

        Import-AWSModule # EC2
        $awsPowerShellLoaded = $true
    } else {

        Write-Warning "AWSPowerShell Module *NOT* installed.  Some tests will not execute."
    }

    Context "Parameter Validation" {

        It "Null Environment Name Should Throw" {

            { Get-HostnamesByEnvironmentName -EnvironmentName $null } | Should Throw
        }

        It "Empty Environment Name Should Throw" {

            { Get-HostnamesByEnvironmentName -EnvironmentName '' } | Should Throw
        }
    }

    Context "Get-Environment Is Called When EnvironmentType Parameter Is Null" {
        Mock -CommandName Get-Environment                     -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-DesignationTagNameByEnvironment -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-InstancesByTag                  -ModuleName $moduleForMock -MockWith { return @()    }

        $result = ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType $null )

        It "Get-Environment Is Called One Time" {

            Assert-MockCalled Get-Environment -Times 1 -Exactly -Scope Context -ModuleName $moduleForMock
        }
    }

    Context "Get-Environment Is Called When EnvironmentType Parameter Is Empty" {
        Mock -CommandName Get-Environment                     -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-DesignationTagNameByEnvironment -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-InstancesByTag                  -ModuleName $moduleForMock -MockWith { return @()    }

        $result = ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType '' )

        It "Get-Environment Is Called One Time" {

            Assert-MockCalled Get-Environment -Times 1 -Exactly -Scope Context -ModuleName $moduleForMock
        }
    }

    Context "Get-Environment Is Not Called When EnvironmentType Parameter Is Provided" {
        Mock -CommandName Get-Environment                     -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-DesignationTagNameByEnvironment -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-InstancesByTag                  -ModuleName $moduleForMock -MockWith { return @()    }

        $result = ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType 'Prod' )

        It "Get-Environment Is Not Called" {

            Assert-MockCalled Get-Environment -Times 0 -Exactly -Scope Context -ModuleName $moduleForMock
        }
    }

    Context "Returns Empty Array When No Instances Are Found" {
        Mock -CommandName Get-Environment                     -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-DesignationTagNameByEnvironment -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-InstancesByTag                  -ModuleName $moduleForMock -MockWith { return @()    }

        It "Is Empty" {

            ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType 'Prod' ) | Should -BeExactly @()
        }
    }

    Context "Sorted Result Does Not Include Null Or Empty Entries" {
        Mock -CommandName Get-Environment                     -ModuleName $moduleForMock -MockWith { return 'Prod' }
        Mock -CommandName Get-DesignationTagNameByEnvironment -ModuleName $moduleForMock -MockWith { return 'Prod' }

        It "Does Not Include Null" {

            if (!($awsPowerShellLoaded)) {

                Set-ItResult -Inconclusive -Because "AWSPowerShell Not Installed"
                continue;
            }

            Mock -CommandName Get-InstancesByTag -ModuleName $moduleForMock -MockWith {
                $testInstance = (New-Object Amazon.EC2.Model.Instance)
                $testInstance.InstanceId = 'Test'

                $nullInstance = (New-Object Amazon.EC2.Model.Instance)
                $nullInstance.InstanceId = $null

                return @( $testInstance, $nullInstance )
            }

            Mock -CommandName Get-InstanceHostname -ModuleName $moduleForMock -MockWith {
                return $Instance.InstanceId.ToUpperInvariant()
            }

            ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType 'Prod' ) | Should -BeExactly @( 'TEST' )
        }

        It "Does Not Include Empty String" {

            if (!($awsPowerShellLoaded)) {

                Set-ItResult -Inconclusive -Because "AWSPowerShell Not Installed"
                continue;
            }

            Mock -CommandName Get-InstancesByTag -ModuleName $moduleForMock -MockWith {
                $testInstance = (New-Object Amazon.EC2.Model.Instance)
                $testInstance.InstanceId = 'Test'

                $emptyInstance = (New-Object Amazon.EC2.Model.Instance)
                $emptyInstance.InstanceId = ''

                return @( $testInstance, $emptyInstance )
            }

            Mock -CommandName Get-InstanceHostname -ModuleName $moduleForMock -MockWith {
                return $Instance.InstanceId.ToUpperInvariant()
            }

            ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType 'Prod' ) | Should -BeExactly @( 'TEST' )
        }

        It "Is Sorted" {

            if (!($awsPowerShellLoaded)) {

                Set-ItResult -Inconclusive -Because "AWSPowerShell Not Installed"
                continue;
            }

            Mock -CommandName Get-InstancesByTag -ModuleName $moduleForMock -MockWith {
                $bInstance = (New-Object Amazon.EC2.Model.Instance)
                $bInstance.InstanceId = 'B'

                $aInstance = (New-Object Amazon.EC2.Model.Instance)
                $aInstance.InstanceId = 'A'

                return @( $bInstance, $aInstance )
            }

            Mock -CommandName Get-InstanceHostname -ModuleName $moduleForMock -MockWith {
                return $Instance.InstanceId.ToUpperInvariant()
            }

            ( Get-HostnamesByEnvironmentName -EnvironmentName 'Test' -EnvironmentType 'Prod' ) | Should -BeExactly @( 'A', 'B' )
        }
    }
}