diff --git a/Public/Array/Get-PfbArraySpace.ps1 b/Public/Array/Get-PfbArraySpace.ps1
index 66688c06..41972daf 100644
--- a/Public/Array/Get-PfbArraySpace.ps1
+++ b/Public/Array/Get-PfbArraySpace.ps1
@@ -7,7 +7,8 @@ function Get-PfbArraySpace {
     .PARAMETER Array
         The FlashBlade connection object. If not specified, uses the default connection.
     .PARAMETER Type
-        Filter by space type (e.g., 'array', 'file-system', 'object-store').
+        Filter by space type. Valid values: 'array', 'file-system', 'object-store'.
+        Defaults to 'array' if not specified.
     .EXAMPLE
         Get-PfbArraySpace
     #>
@@ -17,6 +18,7 @@ function Get-PfbArraySpace {
         [PSCustomObject]$Array,
 
         [Parameter()]
+        [ValidateSet('array', 'file-system', 'object-store')]
         [string]$Type
     )
 
diff --git a/Tests/Get-PfbArraySpace.Tests.ps1 b/Tests/Get-PfbArraySpace.Tests.ps1
new file mode 100644
index 00000000..a7873e84
--- /dev/null
+++ b/Tests/Get-PfbArraySpace.Tests.ps1
@@ -0,0 +1,39 @@
+#Requires -Modules @{ ModuleName = 'Pester'; ModuleVersion = '5.0' }
+
+BeforeAll {
+    Import-Module "$PSScriptRoot/../PureStorageFlashBladePowerShell.psd1" -Force
+    $script:fakeArray = [PSCustomObject]@{ Endpoint = 'fb.example.test'; ApiVersion = '2.0'; AuthToken = 'x' }
+}
+
+Describe 'Get-PfbArraySpace' {
+    BeforeEach {
+        Mock -ModuleName PureStorageFlashBladePowerShell Assert-PfbConnection { }
+        Mock -ModuleName PureStorageFlashBladePowerShell Invoke-PfbApiRequest { }
+    }
+
+    It 'restricts -Type to the three real spec-documented values' {
+        $attr = (Get-Command Get-PfbArraySpace).Parameters['Type'].Attributes |
+            Where-Object { $_ -is [System.Management.Automation.ValidateSetAttribute] }
+        $attr | Should -Not -BeNullOrEmpty
+        $attr.ValidValues | Should -Be @('array', 'file-system', 'object-store')
+    }
+
+    It 'rejects an invalid -Type value before making any API call' {
+        { Get-PfbArraySpace -Type 'bogus' -Array $fakeArray } | Should -Throw
+        Should -Invoke Invoke-PfbApiRequest -ModuleName PureStorageFlashBladePowerShell -Times 0 -Exactly
+    }
+
+    It 'passes a valid -Type through to the query string' {
+        Get-PfbArraySpace -Type 'file-system' -Array $fakeArray
+        Should -Invoke Invoke-PfbApiRequest -ModuleName PureStorageFlashBladePowerShell -Times 1 -Exactly -ParameterFilter {
+            $Method -eq 'GET' -and $Endpoint -eq 'arrays/space' -and $QueryParams['type'] -eq 'file-system'
+        }
+    }
+
+    It 'omits -Type from the query string when not specified (server defaults to array)' {
+        Get-PfbArraySpace -Array $fakeArray
+        Should -Invoke Invoke-PfbApiRequest -ModuleName PureStorageFlashBladePowerShell -Times 1 -Exactly -ParameterFilter {
+            -not $QueryParams.ContainsKey('type')
+        }
+    }
+}