Address Copilot review: document \ return on non-PR; add Get-GitHubPullRequest coverage

Author: MariusStorhaug

scripts/Resolve-PSModuleVersion.Helpers.psm1

@@ -126,11 +126,14 @@ function Get-GitHubPullRequest {
         Reads and validates the GitHub pull request from the event payload.
 
         .DESCRIPTION
-        Loads the GitHub event from the input override or from the event path file,
-        then validates and extracts pull request data.
+        Loads the GitHub event from the input override or from the event path file. On a
+        pull_request event it returns the pull request head ref and labels. On any other
+        event (for example workflow_dispatch or schedule) there is no pull request, so it
+        returns $null and the caller resolves the current version without a version bump.
 
         .OUTPUTS
-        PSCustomObject with HeadRef and Labels properties.
+        PSCustomObject with HeadRef and Labels properties for a pull_request event, or
+        $null when the event has no pull request (non-PR events).
 
         .EXAMPLE
         $pullRequest = Get-GitHubPullRequest

tests/Resolve-PSModuleVersion.Helpers.Tests.ps1

@@ -231,3 +231,30 @@ Describe 'Non-PR event keeps the current version' {
         $result.Prerelease | Should -BeNullOrEmpty
     }
 }
+
+Describe 'Get-GitHubPullRequest' {
+    # Covers the non-PR branch: on an event without a pull_request (workflow_dispatch/schedule)
+    # the function must return $null so the caller keeps the current version, and it must still
+    # return the head ref + labels on a pull_request event.
+    AfterEach {
+        Remove-Item Env:PSMODULE_RESOLVE_PSMODULEVERSION_INPUT_EventJson -ErrorAction SilentlyContinue
+    }
+
+    It 'returns $null when the event has no pull_request (non-PR event)' {
+        $env:PSMODULE_RESOLVE_PSMODULEVERSION_INPUT_EventJson = '{ "action": "workflow_dispatch" }'
+        Get-GitHubPullRequest | Should -BeNullOrEmpty
+    }
+
+    It 'returns the head ref and labels for a pull_request event' {
+        $eventJson = @{
+            pull_request = @{
+                head   = @{ ref = 'feat/example' }
+                labels = @(@{ name = 'patch' }, @{ name = 'prerelease' })
+            }
+        } | ConvertTo-Json -Depth 5
+        $env:PSMODULE_RESOLVE_PSMODULEVERSION_INPUT_EventJson = $eventJson
+        $result = Get-GitHubPullRequest
+        $result.HeadRef | Should -Be 'feat/example'
+        ($result.Labels -join ',') | Should -Be 'patch,prerelease'
+    }
+}