diff --git a/tests/ManifestHelpers.psm1 b/tests/ManifestHelpers.psm1
index b797866..7f93868 100644
--- a/tests/ManifestHelpers.psm1
+++ b/tests/ManifestHelpers.psm1
@@ -36,13 +36,10 @@ function Split-SemVerString {
     [OutputType([hashtable])]
     param(
         [Parameter(Mandatory = $true)]
+        [ValidateNotNullOrEmpty()]
         [string]$VersionString
     )
 
-    if ([string]::IsNullOrEmpty($VersionString)) {
-        throw "VersionString cannot be empty or null"
-    }
-
     # Strip build metadata per SemVer 2.0.0 — it does not affect precedence and is
     # not valid for [System.Version], so it must be removed before further parsing.
     $coreVersion = ($VersionString -split '\+', 2)[0]