diff --git a/build.psm1 b/build.psm1
index 8fc04c04edd3..e0e4d9bdc842 100644
--- a/build.psm1
+++ b/build.psm1
@@ -662,7 +662,8 @@ function Restore-PSModuleToBuild
 
     if($CI.IsPresent)
     {
-        Restore-PSPester -Destination $modulesDir
+        # take the latest version of pester and install it so it may be used
+        Save-Module -Path $modulesDir -Name Pester
     }
 }
 
@@ -987,7 +988,7 @@ function Start-PSPester {
         Write-Warning @"
 Pester module not found.
 Restore the module to '$Pester' by running:
-    Restore-PSPester
+    Save-Module Pester -Path '$binDir/Modules'
 "@
         return;
     }
diff --git a/docs/testing-guidelines/WritingPesterTests.md b/docs/testing-guidelines/WritingPesterTests.md
index df0ea928f060..5866ea9b1154 100755
--- a/docs/testing-guidelines/WritingPesterTests.md
+++ b/docs/testing-guidelines/WritingPesterTests.md
@@ -1,7 +1,11 @@
 ### Writing Pester Tests
-Note that this document does not replace the documents found in the [Pester](https://github.com/pester/pester "Pester") project. This is just
-some quick tips and suggestions for creating Pester tests for this project. The Pester community is vibrant and active, if you have questions
-about Pester or creating tests, the [Pester Wiki](https://github.com/pester/pester/wiki) has a lot of great information.
+Note that this document does not replace the documents found in the [Pester](https://github.com/pester/pester "Pester") project.
+This is just some quick tips and suggestions for creating Pester tests for this project.
+The Pester community is vibrant and active, if you have questions about Pester or creating tests, the [Pester Wiki](https://github.com/pester/pester/wiki) has a lot of great information.
+As of January 2018, PowerShell Core is using Pester version 4 which has some changes from earlier versions.
+See [Migrating from Pester 3 to Pester 4](https://github.com/pester/Pester/wiki/Migrating-from-Pester-3-to-Pester-4) for more information.
+
+
 
 When creating tests, keep the following in mind:
 * Tests should not be overly complicated and test too many things
@@ -16,7 +20,7 @@ Here's the simplest of tests
 Describe "A variable can be assigned and retrieved" {
     It "Create a variable and make sure its value is correct" {
        $a = 1
-       $a | Should be 1
+       $a | Should Be 1
    }
 }
 ```
@@ -27,7 +31,7 @@ If you need to do type checking, that can be done as well
 Describe "One is really one" {
     It "Compare 1 to 1" {
        $a = 1
-       $a | Should be 1
+       $a | Should Be 1
     }
     It "1 is really an int" {
        $i = 1
@@ -42,7 +46,7 @@ alternatively, you could do the following:
 Describe "One is really one" {
     It "Compare 1 to 1" {
        $a = 1
-       $a | Should be 1
+       $a | Should Be 1
     }
     It "1 is really an int" {
        $i = 1
@@ -136,7 +140,7 @@ $testCases = @(
 Describe "A test" {
     It "<a> -xor <b> should be <expectedresult>" -testcase $testcases {
         param ($a, $b, $ExpectedResult)
-        $a -xor $b | Should be $ExpectedResult
+        $a -xor $b | Should Be $ExpectedResult
     }
 }
 ```
@@ -151,7 +155,7 @@ The following example illustrates simple use:
 Context "Get-Random is not random" {
         Mock Get-Random { return 3 }
         It "Get-Random returns 3" {
-            Get-Random | Should be 3
+            Get-Random | Should Be 3
         }
     }
 ```
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Core/Import-Module.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Core/Import-Module.Tests.ps1
index 98d12c4656e3..d0027a1a30e6 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Core/Import-Module.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Core/Import-Module.Tests.ps1
@@ -42,7 +42,7 @@
 
     It "should only load the specified version" {
         Import-Module TestModule -RequiredVersion 1.1
-        (Get-Module TestModule).Version | Should Be "1.1"
+        (Get-Module TestModule).Version | Should BeIn "1.1"
     }
 }
 
@@ -192,7 +192,7 @@ Describe "Import-Module should be case insensitive" -Tags 'CI' {
         Import-Module testMODULE
         $m = Get-Module TESTmodule
         $m | Should BeOfType "System.Management.Automation.PSModuleInfo"
-        $m.Name | Should Be "TESTMODULE"
+        $m.Name | Should BeIn "TESTMODULE"
         mytest | Should BeExactly "hello"
         Remove-Module TestModule
         Get-Module tESTmODULE | Should BeNullOrEmpty
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Core/Out-Default.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Core/Out-Default.Tests.ps1
index b84fba882046..a0ed821d9ff0 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Core/Out-Default.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Core/Out-Default.Tests.ps1
@@ -15,7 +15,7 @@ Describe "Out-Default Tests" -tag CI {
 "@
 
         & $powershell -noprofile -command $script | Should BeExactly 'bye'
-        "TestDrive:\transcript.txt" | Should Contain 'hello'
+        "TestDrive:\transcript.txt" | Should FileContentMatch 'hello'
     }
 
     It "Out-Default reverts transcription state when used more than once in a pipeline" {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Clear-Content.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Clear-Content.Tests.ps1
index 8c9c1c1aea9b..996088c5171b 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Clear-Content.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Clear-Content.Tests.ps1
@@ -64,7 +64,7 @@ Describe "Clear-Content cmdlet tests" -Tags "CI" {
     # we could suppress the WhatIf output here if we use the testhost, but it's not necessary
     It "The filesystem provider supports should process" -skip:(!$IsWindows) {
       clear-content TESTDRIVE:\$file2 -WhatIf
-      "TESTDRIVE:\$file2" | should contain "This is content"
+      "TESTDRIVE:\$file2" | should FileContentMatch "This is content"
     }
 
     It "The filesystem provider should support ShouldProcess (reference ProviderSupportsShouldProcess member)" {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/FileSystem.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/FileSystem.Tests.ps1
index c04b9472a1ac..f514e1e45ce8 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/FileSystem.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/FileSystem.Tests.ps1
@@ -378,8 +378,7 @@ Describe "Handling of globbing patterns" -Tags "CI" {
         BeforeEach {
             $file = New-Item -ItemType File -Path $filePath -Force
         }
-        AfterEach
-        {
+        AfterEach {
             Remove-Item -Force -Recurse -Path $dirPath -ErrorAction SilentlyContinue
             Remove-Item -Force -LiteralPath $newPath -ErrorAction SilentlyContinue
         }
@@ -1392,7 +1391,7 @@ Describe "UNC paths" -Tags 'CI' {
             $testPath = Join-Path "\\localhost" $systemDrive
             & $cmdlet $testPath
             Get-Location | Should BeExactly "Microsoft.PowerShell.Core\FileSystem::$testPath"
-            $children = { Get-ChildItem -ErrorAction Stop } | Should Not Throw
+            $children = Get-ChildItem -ErrorAction Stop
             $children.Count | Should BeGreaterThan 0
         }
         finally {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Move-Item.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Move-Item.Tests.ps1
index e911c9e399a9..d2981962d4b6 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Move-Item.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Move-Item.Tests.ps1
@@ -9,7 +9,7 @@ Describe "Move-Item tests" -Tag "CI" {
         Move-Item $source $target
         test-path $source | Should be $false
         test-path $target | Should be $true
-        "$target" | Should ContainExactly "This is content"
+        "$target" | Should FileContentMatchExactly "This is content"
     }
 
     Context "Move-Item with filters" {
@@ -49,7 +49,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $newBarPath | Should Exist
             $booPath | Should Exist
             $fooPath | Should Exist
-            $newBarPath | Should ContainExactly $barContent
+            $newBarPath | Should FileContentMatchExactly $barContent
         }
         It "Can move to different directory, filtered with -Exclude" {
             Move-Item -Path $filePath -Destination $moveToPath -Exclude "b*" -ErrorVariable e -ErrorAction SilentlyContinue
@@ -58,7 +58,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $newFooPath | Should Exist
             $booPath | Should Exist
             $barPath | Should Exist
-            $newFooPath | Should ContainExactly $fooContent
+            $newFooPath | Should FileContentMatchExactly $fooContent
         }
         It "Can move to different directory, filtered with -Filter" {
             Move-Item -Path $filePath -Destination $moveToPath -Filter "bo*" -ErrorVariable e -ErrorAction SilentlyContinue
@@ -67,7 +67,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $newBooPath | Should Exist
             $barPath | Should Exist
             $fooPath | Should Exist
-            $newBooPath | Should ContainExactly $booContent
+            $newBooPath | Should FileContentMatchExactly $booContent
         }
 
         It "Can rename via move, filtered with -Include" {
@@ -77,7 +77,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $barPath | Should Not Exist
             $booPath | Should Exist
             $fooPath | Should Exist
-            $renameToPath | Should ContainExactly $barContent
+            $renameToPath | Should FileContentMatchExactly $barContent
         }
         It "Can rename via move, filtered with -Exclude" {
             Move-Item -Path $filePath -Destination $renameToPath -Exclude "b*" -ErrorVariable e -ErrorAction SilentlyContinue
@@ -86,7 +86,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $fooPath | Should Not Exist
             $booPath | Should Exist
             $barPath | Should Exist
-            $renameToPath | Should ContainExactly $fooContent
+            $renameToPath | Should FileContentMatchExactly $fooContent
         }
         It "Can rename via move, filtered with -Filter" {
             Move-Item -Path $filePath -Destination $renameToPath -Filter "bo*" -ErrorVariable e -ErrorAction SilentlyContinue
@@ -95,7 +95,7 @@ Describe "Move-Item tests" -Tag "CI" {
             $booPath | Should Not Exist
             $fooPath | Should Exist
             $barPath | Should Exist
-            $renameToPath | Should ContainExactly $booContent
+            $renameToPath | Should FileContentMatchExactly $booContent
         }
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Item.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Item.Tests.ps1
index 076f11f5009a..b764afdbf92c 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Item.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/Rename-Item.Tests.ps1
@@ -9,6 +9,6 @@ Describe "Rename-Item tests" -Tag "CI" {
         Rename-Item $source $target
         test-path $source | Should be $false
         test-path $target | Should be $true
-        "$target" | Should ContainExactly "This is content"
+        "$target" | Should FileContentMatchExactly "This is content"
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Management/TimeZone.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Management/TimeZone.Tests.ps1
index 236b98ca0586..9f2aeb93955a 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Management/TimeZone.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Management/TimeZone.Tests.ps1
@@ -63,7 +63,7 @@ Describe "Get-Timezone test cases" -Tags "CI" {
     It "Call with ListAvailable switch returns a list containing TimeZoneInfo.Local" {
         $observedIdList = Get-TimeZone -ListAvailable | Select-Object -ExpandProperty BaseUtcOffset
         $oneExpectedOffset = ([System.TimeZoneInfo]::Local).BaseUtcOffset
-        $observedIdList -eq $oneExpectedOffset | Should Be $oneExpectedOffset
+        $oneExpectedOffset | Should BeIn $observedIdList
     }
 
     ## The local time zone could be set to UTC or GMT*. In this case, the .NET API returns the region ID
@@ -71,7 +71,7 @@ Describe "Get-Timezone test cases" -Tags "CI" {
     It "Call with ListAvailable switch returns a list containing one returned by Get-TimeZone" {
         $observedIdList = Get-TimeZone -ListAvailable | Select-Object -ExpandProperty BaseUtcOffset
         $oneExpectedOffset = (Get-TimeZone).BaseUtcOffset
-        $observedIdList -eq $oneExpectedOffset | Should Be $oneExpectedOffset
+        $oneExpectedOffset | Should BeIn $observedIdList
     }
 
     It "Call Get-TimeZone using ID param and single item" {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertFrom-StringData.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertFrom-StringData.Tests.ps1
index 2ffa15228cc1..3bbed5132fa7 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertFrom-StringData.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertFrom-StringData.Tests.ps1
@@ -65,8 +65,9 @@ bazz = 2
     It "Should work for multiple lines" {
 	{ ConvertFrom-StringData -StringData $sampleData } | Should Not Throw
 
-	$(ConvertFrom-StringData -StringData $sampleData).Keys   | Should Be "foo", "bar", "bazz"
+    # keys are not order guaranteed
+	$(ConvertFrom-StringData -StringData $sampleData).Keys   | Should BeIn @("foo", "bar", "bazz")
 
-	$(ConvertFrom-StringData -StringData $sampleData).Values | Should Be "0","1","2"
+	$(ConvertFrom-StringData -StringData $sampleData).Values | Should BeIn @("0","1","2")
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Html.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Html.Tests.ps1
index 7471985056b7..9d41fa95a3c2 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Html.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Html.Tests.ps1
@@ -138,7 +138,9 @@ After the object
 
     It "Test ConvertTo-HTML meta with invalid properties should throw warning" {
         $parms = @{"authors"="John Doe";"keywords"="PowerShell,PSv6"}
-        ($customObject | ConvertTo-HTML -Meta $parms 3>&1) -match $parms["authors"]  | Should Be $true
+        # make this a string, rather than an array of string so match will behave
+        [string]$observedProperties = $customObject | ConvertTo-HTML -Meta $parms 3>&1
+        $observedProperties | Should Match $parms["authors"]
     }
 
     It "Test ConvertTo-HTML charset"{
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Export-Alias.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Export-Alias.Tests.ps1
index 045a223bc1d3..a09f66eaea5d 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Export-Alias.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Export-Alias.Tests.ps1
@@ -63,46 +63,46 @@ Describe "Export-Alias DRT Unit Tests" -Tags "CI" {
 
 	It "Export-Alias for Default"{
 		Export-Alias $fulltestpath abcd01 -passthru
-		$fulltestpath| Should ContainExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should FileContentMatchExactly '"abcd01","efgh01","","None"'
     }
 
 	It "Export-Alias As CSV"{
 		Export-Alias $fulltestpath abcd01 -As CSV -passthru
-		$fulltestpath| Should ContainExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should FileContentMatchExactly '"abcd01","efgh01","","None"'
     }
 
 	It "Export-Alias As CSV With Description"{
 		Export-Alias $fulltestpath abcd01 -As CSV -description "My Aliases" -passthru
-		$fulltestpath| Should ContainExactly '"abcd01","efgh01","","None"'
-		$fulltestpath| Should ContainExactly "My Aliases"
+		$fulltestpath| Should FileContentMatchExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should FileContentMatchExactly "My Aliases"
     }
 
 	It "Export-Alias As CSV With Multiline Description"{
 		Export-Alias $fulltestpath abcd01 -As CSV -description "My Aliases\nYour Aliases\nEveryones Aliases" -passthru
-		$fulltestpath| Should ContainExactly '"abcd01","efgh01","","None"'
-		$fulltestpath| Should ContainExactly "My Aliases"
-		$fulltestpath| Should ContainExactly "Your Aliases"
-		$fulltestpath| Should ContainExactly "Everyones Aliases"
+		$fulltestpath| Should FileContentMatchExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should FileContentMatchExactly "My Aliases"
+		$fulltestpath| Should FileContentMatchExactly "Your Aliases"
+		$fulltestpath| Should FileContentMatchExactly "Everyones Aliases"
     }
 
 	It "Export-Alias As Script"{
 		Export-Alias $fulltestpath abcd01 -As Script -passthru
-		$fulltestpath| Should ContainExactly 'set-alias -Name:"abcd01" -Value:"efgh01" -Description:"" -Option:"None"'
+		$fulltestpath| Should FileContentMatchExactly 'set-alias -Name:"abcd01" -Value:"efgh01" -Description:"" -Option:"None"'
     }
 
 	It "Export-Alias As Script With Multiline Description"{
 		Export-Alias $fulltestpath abcd01 -As Script -description "My Aliases\nYour Aliases\nEveryones Aliases" -passthru
-		$fulltestpath| Should ContainExactly 'set-alias -Name:"abcd01" -Value:"efgh01" -Description:"" -Option:"None"'
-		$fulltestpath| Should ContainExactly "My Aliases"
-		$fulltestpath| Should ContainExactly "Your Aliases"
-		$fulltestpath| Should ContainExactly "Everyones Aliases"
+		$fulltestpath| Should FileContentMatchExactly 'set-alias -Name:"abcd01" -Value:"efgh01" -Description:"" -Option:"None"'
+		$fulltestpath| Should FileContentMatchExactly "My Aliases"
+		$fulltestpath| Should FileContentMatchExactly "Your Aliases"
+		$fulltestpath| Should FileContentMatchExactly "Everyones Aliases"
     }
 
 	It "Export-Alias for Force Test"{
 		Export-Alias $fulltestpath abcd01
 		Export-Alias $fulltestpath abcd02 -force
-		$fulltestpath| Should Not ContainExactly '"abcd01","efgh01","","None"'
-		$fulltestpath| Should ContainExactly '"abcd02","efgh02","","None"'
+		$fulltestpath| Should Not FileContentMatchExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should FileContentMatchExactly '"abcd02","efgh02","","None"'
     }
 
 	It "Export-Alias for Force ReadOnly Test" {
@@ -124,9 +124,9 @@ Describe "Export-Alias DRT Unit Tests" -Tags "CI" {
 			$_.FullyQualifiedErrorId | Should be "FileOpenFailure,Microsoft.PowerShell.Commands.ExportAliasCommand"
 		}
 		Export-Alias $fulltestpath abcd03 -force
-		$fulltestpath| Should Not ContainExactly '"abcd01","efgh01","","None"'
-		$fulltestpath| Should Not ContainExactly '"abcd02","efgh02","","None"'
-		$fulltestpath| Should ContainExactly '"abcd03","efgh03","","None"'
+		$fulltestpath| Should Not FileContentMatchExactly '"abcd01","efgh01","","None"'
+		$fulltestpath| Should Not FileContentMatchExactly '"abcd02","efgh02","","None"'
+		$fulltestpath| Should FileContentMatchExactly '"abcd03","efgh03","","None"'
 
 		if ( $IsWindows )
 		{
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Variable.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Variable.Tests.ps1
index 0588c247fe20..c9618be51ee5 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Variable.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Get-Variable.Tests.ps1
@@ -145,7 +145,8 @@ Describe "Get-Variable" -Tags "CI" {
 	It "Should not be able to clear a global scope variable using the local switch" {
 	    New-Variable globalVar -Value 1 -Scope global -Force
 
-	    Get-Variable -Name globalVar -Scope local -ErrorAction SilentlyContinue | Should Throw
+	    Get-Variable -Name globalVar -Scope local -ErrorAction SilentlyContinue -ErrorVariable removeGlobalAsLocal
+	    $removeGlobalAsLocal.FullyQualifiedErrorId | Should Be "VariableNotFound,Microsoft.PowerShell.Commands.GetVariableCommand"
 	}
 
 	It "Should be able to get a global variable when there's one in the script scope" {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Invoke-Item.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Invoke-Item.Tests.ps1
index 297804c7d0ad..b55f2b8030eb 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Invoke-Item.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Invoke-Item.Tests.ps1
@@ -67,7 +67,8 @@ Describe "Invoke-Item basic tests" -Tags "Feature" {
                 Get-Process -Name $notepadProcessName | Stop-Process -Force
                 Invoke-Item -Path $notepad
                 $notepadProcess = Get-Process -Name $notepadProcessName
-                $notepadProcess.Name | Should Be $notepadProcessName
+                # we need BeIn because multiple notepad processes could be running
+                $notepadProcess.Name | Should BeIn $notepadProcessName
                 Stop-Process -InputObject $notepadProcess
             }
         } else {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/New-Variable.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/New-Variable.Tests.ps1
index 1ca0652f783b..64b346810720 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/New-Variable.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/New-Variable.Tests.ps1
@@ -85,8 +85,9 @@ Describe "New-Variable" -Tags "CI" {
     }
 
     It "Should not be able to set the name of a new variable to that of an old variable within same scope when the Force switch is missing" {
-	New-Variable var1
-	(New-Variable var1 -ErrorAction SilentlyContinue) | Should Throw
+        New-Variable var1
+        New-Variable var1 -ErrorAction SilentlyContinue -ErrorVariable newWhenExists
+        $newWhenExists.FullyQualifiedErrorId | Should Be "VariableAlreadyExists,Microsoft.PowerShell.Commands.NewVariableCommand"
     }
 
     It "Should change the value of an already existing variable using the Force switch" {
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Out-File.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Out-File.Tests.ps1
index e11f88413360..46f32b84ac27 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Out-File.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Out-File.Tests.ps1
@@ -11,8 +11,8 @@ Describe "Out-File DRT Unit Tests" -Tags "CI" {
         $tempFile = Join-Path -Path $TestDrive -ChildPath "outfileAppendTest.txt"
         { 'This is first line.' | out-file $tempFile } | Should Not Throw
         { 'This is second line.' | out-file -append $tempFile } | Should Not Throw
-        $tempFile |Should Contain "first"
-        $tempFile |Should Contain "second"
+        $tempFile |Should FileContentMatch "first"
+        $tempFile |Should FileContentMatch "second"
         Remove-Item $tempFile -Force
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Event.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Event.Tests.ps1
index b79014d9b3f9..4cf4ecaa746a 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Event.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Event.Tests.ps1
@@ -12,7 +12,7 @@ Describe "Remove-Event" -Tags "CI" {
 
 	It "Should remove an event given a sourceidentifier" {
 	    { Remove-Event -sourceidentifier PesterTimer }
-	    { Get-Event -ErrorAction SilentlyContinue | Should Not Contain PesterTimer }
+	    { Get-Event -ErrorAction SilentlyContinue | Should Not FileMatchContent PesterTimer }
 	}
 
 	It "Should remove an event given an event identifier" {
@@ -20,19 +20,19 @@ Describe "Remove-Event" -Tags "CI" {
 	    { $events = $events.EventIdentifier }
 	    { Remove-Event -EventIdentifier $events }
 	    { $events = Get-Event -ErrorAction SilentlyContinue}
-	    { $events.SourceIdentifier | Should Not Contain "PesterTimer" }
+	    { $events.SourceIdentifier | Should Not FileMatchContent "PesterTimer" }
 	}
 
 	It "Should be able to remove an event given a pipe from Get-Event" {
 	    { Get-Event -sourceidentifier PesterTimer | Remove-Event }
-	    { Get-Event -ErrorAction SilentlyContinue | Should Not Contain "PesterTimer" }
+	    { Get-Event -ErrorAction SilentlyContinue | Should Not FileMatchContent "PesterTimer" }
 
 	}
 
 	It "Should NOT remove an event given the whatif flag" {
 	    { Remove-Event -sourceidentifier PesterTimer -whatif }
 	    { $events = Get-Event }
-	    { $events.SourceIdentifier  | Should Contain "PesterTimer" }
+	    { $events.SourceIdentifier  | Should FileContentMatch "PesterTimer" }
 	}
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Variable.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Variable.Tests.ps1
index f76483f1d188..626ee055e646 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Variable.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Remove-Variable.Tests.ps1
@@ -5,7 +5,8 @@ Describe "Remove-Variable" -Tags "CI" {
     It "Should throw an error when a dollar sign is used in the variable name place" {
 	New-Variable -Name var1 -Value 4
 
-	Remove-Variable $var1 -ErrorAction SilentlyContinue | Should Throw
+	Remove-Variable $var1 -ErrorAction SilentlyContinue -ErrorVariable err
+	$err.FullyQualifiedErrorId | Should Be "VariableNotFound,Microsoft.PowerShell.Commands.RemoveVariableCommand"
     }
 
     It "Should not throw error when used without the Name field, and named variable is properly specified and exists" {
@@ -25,7 +26,7 @@ Describe "Remove-Variable" -Tags "CI" {
     }
 
     It "Should throw error when used with Name field, and named variable does not exist" {
-	Remove-Variable -Name nonexistentVariable -ErrorAction SilentlyContinue | Should Throw
+	{ Remove-Variable -Name nonexistentVariable -ErrorAction Stop } | Should Throw
     }
 
     It "Should be able to remove a set of variables using wildcard characters" {
@@ -87,7 +88,7 @@ Describe "Remove-Variable" -Tags "CI" {
     It "Should throw an error when attempting to remove a read-only variable and the Force switch is not used" {
 	New-Variable -Name var1 -Value 2 -Option ReadOnly
 
-	Remove-Variable -Name var1 -ErrorAction SilentlyContinue | Should Throw
+	{ Remove-Variable -Name var1 -ErrorAction Stop } | Should Throw
 
 	$var1 | Should Be 2
 
@@ -99,7 +100,7 @@ Describe "Remove-Variable" -Tags "CI" {
 
 	Remove-Variable -Name var1 -Force
 
-	$var1 | Should Be # Nothing.  It should be nothing at all.
+	$var1 | Should BeNullOrEmpty
     }
 
     Context "Scope Tests" {
@@ -108,73 +109,73 @@ Describe "Remove-Variable" -Tags "CI" {
 
 	    Remove-Variable -Name var1 -Scope global
 
-	    $var1 | Should Be #Nothing.
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should not be able to clear a global variable using the local switch" {
 	    New-Variable -Name var1 -Value "context" -Scope global
 
-	    Remove-Variable -Name var1 -Scope local -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope local -ErrorAction Stop } | Should Throw
 
 	    $var1 | Should Be "context"
 
 	    Remove-Variable -Name var1 -Scope global
-	    $var1 | Should Be # Nothing
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should not be able to clear a global variable using the script switch" {
 	    New-Variable -Name var1 -Value "context" -Scope global
 
-	    Remove-Variable -Name var1 -Scope local -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope local -ErrorAction Stop } | Should Throw
 
 	    $var1 | Should Be "context"
 
 	    Remove-Variable -Name var1 -Scope global
-	    $var1 | Should Be # Nothing
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should be able to remove an item locally using the local switch" {
 	    New-Variable -Name var1 -Value "context" -Scope local
 
-	    Remove-Variable -Name var1 -Scope local -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope local -ErrorAction Stop } | Should Throw
 
-	    $var1 | Should Be # Nothing
+	    $var1 | Should Be context
 	}
 
 	It "Should be able to remove an item locally using the global switch" {
 	    New-Variable -Name var1 -Value "context" -Scope local
 
-	    Remove-Variable -Name var1 -Scope global -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope global -ErrorAction Stop } | Should Throw
 
 	    $var1 | Should Be "context"
 
 	    Remove-Variable -Name var1 -Scope local
-	    $var1 | Should Be # Nothing
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should be able to remove a local variable using the script scope switch" {
 	    New-Variable -Name var1 -Value "context" -Scope local
 
-	    Remove-Variable -Name var1 -Scope script -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope script -ErrorAction Stop } | Should Throw
 
 	    $var1 | Should Be "context"
 
 	    Remove-Variable -Name var1 -Scope local
-	    $var1 | Should Be # Nothing
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should be able to remove a script variable created using the script switch" {
 	    New-Variable -Name var1 -Value "context" -Scope script
 
-	    Remove-Variable -Name var1 -Scope script | Should Throw
+	    { Remove-Variable -Name var1 -Scope script } | Should Not Throw
 
-	    $var1 | Should Be # Nothing
+	    $var1 | Should BeNullOrEmpty
 	}
 
 	It "Should not be able to remove a global script variable that was created using the script scope switch" {
 	    New-Variable -Name var1 -Value "context" -Scope script
 
-	    Remove-Variable -Name var1 -Scope global -ErrorAction SilentlyContinue | Should Throw
+	    { Remove-Variable -Name var1 -Scope global -ErrorAction Stop } | Should Throw
 
 	    $var1 | Should Be "context"
 	}
@@ -200,7 +201,7 @@ Describe "Remove-Variable basic functionality" -Tags "CI" {
 		catch
 		{
 			$_.CategoryInfo | Should Match "SessionStateUnauthorizedAccessException"
-			$_.FullyQualifiedErrorId | Should be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
+			$_.FullyQualifiedErrorId | Should Be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
 		}
 	}
 
@@ -214,7 +215,7 @@ Describe "Remove-Variable basic functionality" -Tags "CI" {
 		catch
 		{
 			$_.CategoryInfo| Should Match "SessionStateUnauthorizedAccessException"
-			$_.FullyQualifiedErrorId | Should be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
+			$_.FullyQualifiedErrorId | Should Be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
 		}
 		Remove-Variable foo -Force
 		$var1 = Get-Variable -Name foo -EA SilentlyContinue
@@ -231,7 +232,7 @@ Describe "Remove-Variable basic functionality" -Tags "CI" {
 		catch
 		{
 			$_.CategoryInfo | Should Match "SessionStateUnauthorizedAccessException"
-			$_.FullyQualifiedErrorId | Should be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
+			$_.FullyQualifiedErrorId | Should Be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
 		}
 
 		try
@@ -242,7 +243,7 @@ Describe "Remove-Variable basic functionality" -Tags "CI" {
 		catch
 		{
 			$_.CategoryInfo | Should Match "SessionStateUnauthorizedAccessException"
-			$_.FullyQualifiedErrorId | Should be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
+			$_.FullyQualifiedErrorId | Should Be "VariableNotRemovable,Microsoft.PowerShell.Commands.RemoveVariableCommand"
 		}
 	}
 
@@ -258,7 +259,7 @@ Describe "Remove-Variable basic functionality" -Tags "CI" {
 			catch
 			{
 				$_.CategoryInfo | Should Match "ItemNotFoundException"
-				$_.FullyQualifiedErrorId | Should be "VariableNotFound,Microsoft.PowerShell.Commands.GetVariableCommand"
+				$_.FullyQualifiedErrorId | Should Be "VariableNotFound,Microsoft.PowerShell.Commands.GetVariableCommand"
 			}
 		}
 
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Select-String.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Select-String.Tests.ps1
index fc937951bbd8..9513a0846d84 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Select-String.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Select-String.Tests.ps1
@@ -104,7 +104,7 @@ Describe "Select-String" -Tags "CI" {
 	It "Should return the name of the file and the string that 'string' is found if there is only one lines that has a match" {
 	    $expected = $testInputFile + ":1:This is a text string, and another string"
 
-	    Select-String $(Split-Path $testInputFile -NoQualifier) -Pattern "string" | Should Be $expected
+	    Select-String $testInputFile -Pattern "string" | Should Be $expected
 	}
 
 	It "Should return all strings where 'second' is found in testfile1 if there is only one lines that has a match" {
@@ -148,8 +148,7 @@ Describe "Select-String" -Tags "CI" {
 	    $expected  = "testfile1.txt:3:This is the third line"
 
 	    $relativePath = Join-Path -Path $testDirectory -ChildPath ".."
-	    $relativePath = Join-Path -Path $relativePath -ChildPath ".."
-	    $relativePath = Join-Path -Path $relativePath -ChildPath (Split-Path $testDirectory -NoQualifier)
+	    $relativePath = Join-Path -Path $relativePath -ChildPath $TestDirectory.Name
 	    $relativePath = Join-Path -Path $relativePath -ChildPath testfile1.txt
 	    Select-String third $relativePath  | Should Match $expected
 	}
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Set-PSBreakpoint.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Set-PSBreakpoint.Tests.ps1
index a9750e923650..d25630ff4c8d 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Set-PSBreakpoint.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Set-PSBreakpoint.Tests.ps1
@@ -67,8 +67,8 @@ set-psbreakpoint -command foo
 
     It "-script and -line can take multiple items" {
         $brk = sbp -line 11,12,13 -column 1 -script $scriptFileName,$scriptFileName
-        $brk.Line | Should Be 11,12,13
-        $brk.Column | Should Be 1
+        $brk.Line | Should BeIn 11,12,13
+        $brk.Column | Should BeIn 1
         Remove-PSBreakPoint -Id $brk.Id
     }
 
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Error.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Error.Tests.ps1
index 5e15f20ea6ae..96b8913188a9 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Error.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Error.Tests.ps1
@@ -75,14 +75,12 @@ Describe "Write-Error Tests" -Tags "CI" {
         $e.CategoryInfo.GetMessage() | Should Be 'NotSpecified: (fooTargetName:fooTargetType) [fooAct], fooReason'
     }
 
-    It "Should be able to throw" {
-    	Write-Error "test throw" -ErrorAction SilentlyContinue | Should Throw
+    It "Should be able to throw with -ErrorAction stop" {
+    	{ Write-Error "test throw" -ErrorAction Stop } | Should Throw
     }
 
     It "Should throw a non-terminating error" {
-        Write-Error "test throw" -ErrorAction SilentlyContinue
-
-        1 + 1 | Should Be 2
+        { Write-Error "test throw" -ErrorAction SilentlyContinue } | Should Not Throw
     }
 
     It "Should trip an exception using the exception switch" {
@@ -106,17 +104,17 @@ Describe "Write-Error Tests" -Tags "CI" {
         $theError = "Error: Too many input values."
         write-error -message $theError -category InvalidArgument -ErrorAction SilentlyContinue
 
-        $error[0]| Should Be $theError
+        [string]$error[0]| Should Be $theError
     }
 
-    It "ErrorRecord should not be truncated" {
+    It "ErrorRecord should not be truncated or have inserted newlines when redirected from another process" {
         $longtext = "0123456789"
         while ($longtext.Length -lt [console]::WindowWidth) {
             $longtext += $longtext
         }
-        pwsh -c Write-Error -Message $longtext 2>&1 > $testdrive\error.txt
-        $e = Get-Content -Path $testdrive\error.txt
-        $e.Count | Should BeExactly 4
-        $e[0] | Should Match $longtext
+        $pwsh = $pshome + "/pwsh"
+        $result = & $pwsh -c Write-Error -Message $longtext 2>&1
+        $result.Count | Should BeExactly 4
+        $result[0] | Should Match $longtext
     }
 }
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Output.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Output.Tests.ps1
index bca5d13a2393..3d00127011b4 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Output.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Output.Tests.ps1
@@ -16,7 +16,8 @@ Describe "Write-Output DRT Unit Tests" -Tags "CI" {
 
     It "Works with NoEnumerate switch" {
         $objectWritten = 1, 2.2, @("John", "Smith", 10), "abc"
-        Write-Output $objectWritten -NoEnumerate 6>&1 | Should be  '1 2.2 System.Object[] abc'
+        [string]$s = Write-Output $objectWritten -NoEnumerate 6>&1 
+        $s | Should be  '1 2.2 System.Object[] abc'
     }
 }
 
diff --git a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Stream.Tests.ps1 b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Stream.Tests.ps1
index 10c5de490f43..d8507e9573dc 100644
--- a/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Stream.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.PowerShell.Utility/Write-Stream.Tests.ps1
@@ -15,15 +15,6 @@ Describe "Stream writer tests" -Tags "CI" {
 
     }
 
-    function Get-OutputResults
-    {
-        # Get the contents of the targetfile.
-        # Make the array a string for less brittle testing
-        $output = $(Get-Content $args[0])
-        [String]::Join([Environment]::NewLine, $output )
-
-        return $output
-    }
     Context "Redirect Stream Tests" {
         # These tests validate that a stream is actually being written to by redirecting the output of that stream
 
@@ -36,28 +27,20 @@ Describe "Stream writer tests" -Tags "CI" {
 
         It "Should write error messages to the error stream" {
             Write-Error "Testing Error" 2>&1 > $targetfile
-
-            $result = Get-OutputResults $targetfile
             # The contents of the error stream should contain the expected text
-            $result -match ": Testing Error" | Should Be $true
+            $targetfile | Should FileContentMatch ": Testing Error"
         }
 
         It "Should write debug messages to the debug stream" {
             Write-Messages -Debug -EA SilentlyContinue 5>&1 > $targetfile
-
-            $result = Get-OutputResults $targetfile
-
             # The contents of the debug stream should contain the expected text
-            $result -match "Debug Message" | Should Be $true
+            $targetfile | Should FileContentMatch "Debug Message"
         }
 
         It "Should write messages to the verbose stream" {
             Write-Messages -Verbose 4>&1 > $targetfile
-
-            $result = Get-OutputResults $targetfile
-
             # The contents of the debug stream should contain the expected text
-            $result -match "Verbose Message" | Should Be $true
+            $targetfile | Should FileContentMatch "Verbose Message"
         }
     }
 
@@ -83,7 +66,7 @@ Describe "Stream writer tests" -Tags "CI" {
             $ps.Dispose()
         }
 
-       It "Write-Information outputs an information object" -Pending:($IsMacOS) {
+       It "Write-Information outputs an information object" {
             # redirect the streams is sufficient
             $result = Write-Information "Test Message" *>&1
             $result.NativeThreadId | Should Not Be 0
@@ -91,7 +74,7 @@ Describe "Stream writer tests" -Tags "CI" {
             $result | Should BeOfType System.Management.Automation.InformationRecord
 
             # Use Match instead of Be so we can avoid dealing with a potential domain name
-            $result.Computer | Should Match "^($([environment]::MachineName)){1}(\.[a-zA-Z0-9]+)*$"
+            $result.Computer | Should Match "^($([environment]::MachineName)){1}(\.[a-zA-Z0-9]+)*$|^localhost$"
             if ($IsWindows)
             {
                 $result.User | Should Match ".*${env:USERNAME}"
diff --git a/test/powershell/Modules/Microsoft.Powershell.Host/Start-Transcript.Tests.ps1 b/test/powershell/Modules/Microsoft.Powershell.Host/Start-Transcript.Tests.ps1
index 2d3c28aba223..f31ee6855c4e 100644
--- a/test/powershell/Modules/Microsoft.Powershell.Host/Start-Transcript.Tests.ps1
+++ b/test/powershell/Modules/Microsoft.Powershell.Host/Start-Transcript.Tests.ps1
@@ -32,9 +32,9 @@ Describe "Start-Transcript, Stop-Transcript tests" -tags "CI" {
                     $ps.addscript("Stop-Transcript").Invoke()
 
                     Test-Path $outputFilePath | Should be $true
-                    $outputFilePath | should contain "Get-Date"
+                    $outputFilePath | should FileContentMatch "Get-Date"
                     if($append) {
-                        $outputFilePath | Should contain $content
+                        $outputFilePath | Should FileContentMatch $content
                     }
                 }
             } finally {
@@ -122,7 +122,7 @@ Describe "Start-Transcript, Stop-Transcript tests" -tags "CI" {
         }
 
         Test-Path $transcriptFilePath | Should be $true
-        $transcriptFilePath | Should contain "After Dispose"
+        $transcriptFilePath | Should FileContentMatch "After Dispose"
     }
 
     It "Transcription should be closed if the only runspace gets closed" {
@@ -131,8 +131,8 @@ Describe "Start-Transcript, Stop-Transcript tests" -tags "CI" {
         Invoke-Expression $powerShellCommand
 
         Test-Path $transcriptFilePath | Should be $true
-        $transcriptFilePath | Should contain "Before Dispose"
-        $transcriptFilePath | Should contain "PowerShell transcript end"
+        $transcriptFilePath | Should FileContentMatch "Before Dispose"
+        $transcriptFilePath | Should FileContentMatch "PowerShell transcript end"
     }
 
     It "Transcription should record native command output" {
@@ -144,6 +144,6 @@ Describe "Start-Transcript, Stop-Transcript tests" -tags "CI" {
         Test-Path $transcriptFilePath | Should be $true
 
         $machineName = [System.Environment]::MachineName
-        $transcriptFilePath | Should contain $machineName
+        $transcriptFilePath | Should FileContentMatch $machineName
     }
 }
diff --git a/test/powershell/engine/Basic/CommandDiscovery.Tests.ps1 b/test/powershell/engine/Basic/CommandDiscovery.Tests.ps1
index 3a5bacf0fb80..3659e1830153 100644
--- a/test/powershell/engine/Basic/CommandDiscovery.Tests.ps1
+++ b/test/powershell/engine/Basic/CommandDiscovery.Tests.ps1
@@ -90,7 +90,7 @@
 
         foreach($command in $commands)
         {
-            $command.GetType().Name | should be @("AliasInfo","FunctionInfo","CmdletInfo","FilterInfo")
+            $command.GetType().Name | Should BeIn @("AliasInfo","FunctionInfo","CmdletInfo","FilterInfo")
         }
     }
 
@@ -102,4 +102,4 @@
     It "Get- is prepended to commands" {
         (& 'location').Path | Should Be (get-location).Path
     }
-}
\ No newline at end of file
+}