🪲 [Fix]: Improve test results failure handling and reporting (#6)

The action now provides more detailed and actionable error messages when
test results fail. When tests don't execute properly or result files are
missing, you'll receive specific information about what went wrong,
making it easier to diagnose and fix issues with your test suites.

- Fixes PSModule/Process-PSModule#223

## Improved Error Reporting

The action now generates specific error messages for each type of test
failure, including:
- Missing result files
- Tests that weren't executed
- Failed test results
- No tests reported
- No tests passed
- Inconclusive tests
- Tests that weren't run

Each error message clearly identifies which test suite and result file
is affected, helping you quickly locate and resolve issues.

## Safer Property Access

The action now checks for null values before accessing test result
properties (Tests, Passed, Failed, Inconclusive, NotRun). This prevents
errors when processing incomplete or malformed test result files.

## Better Categorization

Missing result files are now tracked separately from unexecuted tests,
providing clearer insight into whether a test file wasn't found in the
artifacts or if it was present but marked as not executed.

Author: MariusStorhaug

scripts/main.ps1

@@ -75,8 +75,9 @@ LogGroup 'Expected test suites' {
 $isFailure = $false
 
 $testResults = [System.Collections.Generic.List[psobject]]::new()
-$failedTests = [System.Collections.Generic.List[psobject]]::new()
-$unexecutedTests = [System.Collections.Generic.List[psobject]]::new()
+$failedTests = [System.Collections.Generic.List[string]]::new()
+$unexecutedTests = [System.Collections.Generic.List[string]]::new()
+$missingResultFiles = [System.Collections.Generic.List[string]]::new()
 $totalErrors = 0
 
 foreach ($expected in $expectedTestSuites) {
@@ -109,14 +110,21 @@ foreach ($expected in $expectedTestSuites) {
     }
 
     # Determine if there’s any failure for this single test file
+    $hasTestsValue = $null -ne $result.Tests
+    $hasPassedValue = $null -ne $result.Passed
+    $hasFailedValue = $null -ne $result.Failed
+    $hasInconclusiveValue = $null -ne $result.Inconclusive
+    $hasNotRunValue = $null -ne $result.NotRun
+
     $testFailure = (
         $result.Result -ne 'Passed' -or
         $result.Executed -ne $true -or
         $result.ResultFilePresent -eq $false -or
-        $result.Tests -eq 0 -or
-        $result.Passed -eq 0 -or
-        $result.Failed -gt 0 -or
-        $result.Inconclusive -gt 0
+        ($hasTestsValue -and $result.Tests -eq 0) -or
+        ($hasPassedValue -and $hasTestsValue -and $result.Tests -gt 0 -and $result.Passed -eq 0) -or
+        ($hasFailedValue -and $result.Failed -gt 0) -or
+        ($hasInconclusiveValue -and $result.Inconclusive -gt 0) -or
+        ($hasNotRunValue -and $result.NotRun -gt 0)
     )
 
     if ($testFailure) {
@@ -133,16 +141,54 @@ foreach ($expected in $expectedTestSuites) {
     $logGroupName = $expected.Name -replace '-TestResult-Report.*', ''
 
     LogGroup " - $color$logGroupName$reset" {
+        $failureReasons = [System.Collections.Generic.List[string]]::new()
+
+        if ($result.ResultFilePresent -eq $false) {
+            $missingResultFiles.Add($expected.Name)
+            $null = $failureReasons.Add("Result file '$($expected.Name)' was not found in the artifacts.")
+        }
+
         if ($result.Executed -eq $false) {
             $unexecutedTests.Add($expected.Name)
-            Write-GitHubError "Test was not executed as reported in file: $($expected.Name)"
-            $totalErrors++
-        } elseif ($result.Result -eq 'Failed') {
-            $failedTests.Add($expected.Name)
-            Write-GitHubError "Test result explicitly marked as Failed in file: $($expected.Name)"
+            $null = $failureReasons.Add("Test execution flag is false in file: $($expected.Name)")
+        }
+
+        if ($result.Result -and $result.Result -ne 'Passed') {
+            if ($failedTests -notcontains $expected.Name) {
+                $failedTests.Add($expected.Name)
+            }
+            $null = $failureReasons.Add("Test result value '$($result.Result)' indicates failure in file: $($expected.Name)")
+        }
+
+        if ($hasTestsValue -and $result.Tests -eq 0) {
+            $null = $failureReasons.Add("No tests were reported in file: $($expected.Name)")
+        }
+
+        if ($hasPassedValue -and $hasTestsValue -and $result.Tests -gt 0 -and $result.Passed -eq 0) {
+            $null = $failureReasons.Add("No tests passed according to file: $($expected.Name)")
+        }
+
+        if ($hasFailedValue -and $result.Failed -gt 0) {
+            if ($failedTests -notcontains $expected.Name) {
+                $failedTests.Add($expected.Name)
+            }
+            $null = $failureReasons.Add("$($result.Failed) tests failed in file: $($expected.Name)")
+        }
+
+        if ($hasInconclusiveValue -and $result.Inconclusive -gt 0) {
+            $null = $failureReasons.Add("$($result.Inconclusive) tests were inconclusive in file: $($expected.Name)")
+        }
+
+        if ($hasNotRunValue -and $result.NotRun -gt 0) {
+            $null = $failureReasons.Add("$($result.NotRun) tests were not run in file: $($expected.Name)")
+        }
+
+        foreach ($reason in $failureReasons) {
+            Write-GitHubError $reason
             $totalErrors++
         }
-        $result | Format-Table | Out-String
+
+        Write-Host "$($result | Format-Table | Out-String)"
     }
 
     if ($result.ResultFilePresent) {
@@ -181,6 +227,10 @@ LogGroup " - $color`Summary$reset" {
         Write-Host 'Unexecuted Test Files'
         $unexecutedTests | ForEach-Object { Write-Host " - $_" }
     }
+    if ($missingResultFiles.Count -gt 0) {
+        Write-Host 'Missing Test Result Files'
+        $missingResultFiles | ForEach-Object { Write-Host " - $_" }
+    }
 }
 
 exit $totalErrors