Add option to disable v5 syntax

src/Pester.RSpec.ps1

@@ -389,6 +389,9 @@ function New-PesterConfiguration {
       ErrorAction: Controls if Should throws on error. Use 'Stop' to throw on error, or 'Continue' to fail at the end of the test.
       Default value: 'Stop'
 
+      DisableV5: Disables usage of Should -Be assertions, that are replaced by Should-Be in version 6.
+      Default value: $false
+
     Debug:
       ShowFullErrors: Show full errors including Pester internal stack. This property is deprecated, and if set to true it will override Output.StackTraceVerbosity to 'Full'.
       Default value: $false

src/csharp/Pester/ShouldConfiguration.cs

@@ -22,6 +22,7 @@ namespace Pester
     public class ShouldConfiguration : ConfigurationSection
     {
         private StringOption _errorAction;
+        private BoolOption _disableV5;
 
         public static ShouldConfiguration Default { get { return new ShouldConfiguration(); } }
 
@@ -33,11 +34,13 @@ public static ShouldConfiguration ShallowClone(ShouldConfiguration configuration
         public ShouldConfiguration() : base("Should configuration.")
         {
             ErrorAction = new StringOption("Controls if Should throws on error. Use 'Stop' to throw on error, or 'Continue' to fail at the end of the test.", "Stop");
+            DisableV5 = new BoolOption("Disables usage of Should -Be assertions, that are replaced by Should-Be in version 6.", false);
         }
 
         public ShouldConfiguration(IDictionary configuration) : this()
         {
             configuration?.AssignObjectIfNotNull<string>(nameof(ErrorAction), v => ErrorAction = v);
+            configuration?.AssignValueIfNotNull<bool>(nameof(DisableV5), v => DisableV5 = v);
         }
 
         public StringOption ErrorAction
@@ -55,5 +58,21 @@ public StringOption ErrorAction
                 }
             }
         }
+
+        public BoolOption DisableV5
+        {
+            get { return _disableV5; }
+            set
+            {
+                if (_disableV5 == null)
+                {
+                    _disableV5 = value;
+                }
+                else
+                {
+                    _disableV5 = new BoolOption(_disableV5, value.Value);
+                }
+            }
+        }
     }
 }

src/functions/assertions/Should.ps1

@@ -122,18 +122,22 @@ function Should {
             $shouldThrow = 'Stop' -eq $PSBoundParameters["ErrorAction"]
         }
 
+        # first check if we are in the context of Pester, if not we will always throw, and won't disable Should:
+        # This check is slightly hacky, here we are reaching out the the caller session state and
+        # look for $______parameters which we know we are using inside of the Pester runtime to
+        # keep the current invocation context, when we find it, we are able to add non-terminating
+        # errors without throwing and terminating the test.
+        $pesterRuntimeInvocationContext = $PSCmdlet.SessionState.PSVariable.GetValue('______parameters')
+        $isInsidePesterRuntime = $null -ne $pesterRuntimeInvocationContext
+
+        if ($isInsidePesterRuntime -and $pesterRuntimeInvocationContext.Configuration.Should.DisableV5.Value) {
+            throw "Pester Should -Be syntax is disabled. Use Should-Be (without space), or enable it by setting: `$PesterPreference.Should.DisableV5 = `$false"
+        }
+
         if ($null -eq $shouldThrow -or -not $shouldThrow) {
             # we are sure that we either:
             #    - should not throw because of explicit ErrorAction, and need to figure out a place where to collect the error
             #    - or we don't know what to do yet and need to figure out what to do based on the context and settings
-
-            # first check if we are in the context of Pester, if not we will always throw:
-            # this is slightly hacky, here we are reaching out the the caller session state and
-            # look for $______parameters which we know we are using inside of the Pester runtime to
-            # keep the current invocation context, when we find it, we are able to add non-terminating
-            # errors without throwing and terminating the test
-            $pesterRuntimeInvocationContext = $PSCmdlet.SessionState.PSVariable.GetValue('______parameters')
-            $isInsidePesterRuntime = $null -ne $pesterRuntimeInvocationContext
             if (-not $isInsidePesterRuntime) {
                 $shouldThrow = $true
             }

tst/Pester.RSpec.Configuration.ts.ps1

@@ -135,6 +135,10 @@ i -PassThru:$PassThru {
             [PesterConfiguration]::Default.Should.ErrorAction.Value | Verify-Equal 'Stop'
         }
 
+        t "Should.DisableV5 is `$false" {
+            [PesterConfiguration]::Default.Should.DisableV5.Value | Verify-Equal $false
+        }
+
         # Debug configuration
         t "Debug.ShowFullErrors is `$false" {
             [PesterConfiguration]::Default.Debug.ShowFullErrors.Value | Verify-False
@@ -1140,7 +1144,7 @@ i -PassThru:$PassThru {
                     Throw       = $true
                 }
                 Output = @{
-                    CIFormat = 'None'
+                    CIFormat   = 'None'
                     CILogLevel = 'Something'
                 }
             }
@@ -1152,7 +1156,7 @@ i -PassThru:$PassThru {
     b 'Output.RenderMode' {
         t 'Output.RenderMode is Plaintext when set to Auto (default) and env:NO_COLOR is set' {
             $c = [PesterConfiguration] @{
-                Run    = @{
+                Run = @{
                     ScriptBlock = { }
                     PassThru    = $true
                 }
@@ -1225,7 +1229,7 @@ i -PassThru:$PassThru {
             $pesterPath = Get-Module Pester | Select-Object -ExpandProperty Path
             try {
                 $ps = [PowerShell]::Create()
-                $ps.AddCommand('Set-StrictMode').AddParameter('Version','Latest') > $null
+                $ps.AddCommand('Set-StrictMode').AddParameter('Version', 'Latest') > $null
                 $ps.AddStatement().AddScript("Import-Module '$pesterPath' -Force") > $null
                 $ps.AddStatement().AddScript('$c = [PesterConfiguration]@{Run = @{ScriptBlock={ describe "d1" { it "i1" { } } };PassThru=$true};Output=@{RenderMode="Auto"}}') > $null
                 $ps.AddStatement().AddScript('Invoke-Pester -Configuration $c') > $null
@@ -1243,7 +1247,7 @@ i -PassThru:$PassThru {
 
         t 'Each non-Auto option can be set and updated' {
             $c = [PesterConfiguration] @{
-                Run    = @{
+                Run = @{
                     ScriptBlock = { }
                     PassThru    = $true
                 }
@@ -1277,7 +1281,8 @@ i -PassThru:$PassThru {
             try {
                 Invoke-Pester -Configuration $c
                 $true | Verify-False # Should not get here
-            } catch {
+            }
+            catch {
                 $_.Exception.Message -match "Output.RenderMode must be .* it was 'Something'" | Verify-True
                 $failed = $true
             }
@@ -1323,4 +1328,38 @@ i -PassThru:$PassThru {
             { Invoke-Pester -Configuration $c } | Verify-Throw
         }
     }
+
+    b "Should.DisableV5" {
+        t "Disabling V5 assertions makes Should -Be throw" {
+            $c = [PesterConfiguration]@{
+                Run    = @{
+                    ScriptBlock = { Describe 'a' { It 'b' { 1 | Should -Be 1 } } }
+                    PassThru    = $true
+                }
+                Should = @{
+                    DisableV5 = $true
+                }
+            }
+
+            $r = Invoke-Pester -Configuration $c
+            $err = $r.Containers.Blocks.Tests.ErrorRecord
+
+            $err | Verify-Equal 'Pester Should -Be syntax is disabled. Use Should-Be (without space), or enable it by setting: $PesterPreference.Should.DisableV5 = $false'
+        }
+
+        t "Enabling V5 assertions makes Should -Be pass" {
+            $c = [PesterConfiguration]@{
+                Run    = @{
+                    ScriptBlock = { Describe 'a' { It 'b' { 1 | Should -Be 1 } } }
+                    PassThru    = $true
+                }
+                Should = @{
+                    DisableV5 = $false
+                }
+            }
+
+            $r = Invoke-Pester -Configuration $c
+            $r.Result | Verify-Equal "Passed"
+        }
+    }
 }