[devops] Improve GitHub comment when the build fails. (xamarin#20584)

Currently we get a message saying all the tests failed catastrophically.

Example:
xamarin#20434 (comment)

This is both confusing and scary, so change the comment to say that the
build
failed instead.

---------

Co-authored-by: Manuel de la Pena <mandel@microsoft.com>

tools/devops/automation/scripts/TestResults.Tests.ps1

@@ -74,6 +74,11 @@ Describe "TestResults tests" {
 "@
         $stageDependencies = @"
 {    
+  "build_macos_tests": {
+    "build_macos_tests_job": {
+      "result": "Succeeded"
+    }
+  },
   "configure_build": {
     "configure": {
       "outputs": {
@@ -152,6 +157,11 @@ Describe "TestResults tests" {
 
         $stageDependenciesWithMissingResults = @"
 {
+  "build_macos_tests": {
+    "build_macos_tests_job": {
+      "result": "Succeeded"
+    }
+  },
   "configure_build": {
     "configure": {
       "outputs": {
@@ -193,6 +203,31 @@ Describe "TestResults tests" {
     }
 }
 "@
+        $stageDependenciesWithBuildFailure = @"
+{
+  "build_macos_tests": {
+    "build_macos_tests_job": {
+      "outputs": {
+        "fix_commit.GIT_HASH": "8a881722232ef37ed73f8926acd113a6ccc8eafd",
+        "configuration.BuildNugets": "True",
+        "configuration.BuildPkgs": "True",
+        "configuration.PR_ID": "20434",
+        "configuration.RunSampleTests": "",
+        "configuration.SignPkgs": "True",
+        "build.TESTS_BOT": "XAMBOT-1001.Sonoma"
+      },
+      "identifier": null,
+      "name": "build_macos_tests_job",
+      "attempt": 1,
+      "startTime": null,
+      "finishTime": null,
+      "state": "NotStarted",
+      "result": "Failed"
+    }
+  }
+}
+"@
+
     }
 
     It "is correctly created" {
@@ -508,6 +543,30 @@ Describe "TestResults tests" {
 :white_check_mark: dotnettests (Multiple platforms): All 7 tests passed. [Html Report (VSDrops)](vsdropsIndex/simulator_testsdotnettests_Multiple-1/;/tests/vsdrops_index.html) [Download](/_apis/build/builds//artifacts?artifactName=HtmlReport-simulator_testsdotnettests_Multiple-1&api-version=6.0&`$format=zip)
 :white_check_mark: dotnettests (tvOS): All 4 tests passed. [Html Report (VSDrops)](vsdropsIndex/simulator_testsdotnettests_tvOS-1/;/tests/vsdrops_index.html) [Download](/_apis/build/builds//artifacts?artifactName=HtmlReport-simulator_testsdotnettests_tvOS-1&api-version=6.0&`$format=zip)
 
+[comment]: <> (This is a test result report added by Azure DevOps)
+"
+        }
+
+        It "computes the right summary with build failure" {
+            $VerbosePreference = "Continue"
+            $Env:MyVerbosePreference = 'Continue'
+
+
+            $parallelResults = New-ParallelTestsResults -Path "path" -StageDependencies "$stageDependenciesWithBuildFailure" -Context "context" -VSDropsIndex "vsdropsIndex"
+
+            $parallelResults.IsSuccess() | Should -Be $false
+
+            $sb = [System.Text.StringBuilder]::new()
+            $parallelResults.WriteComment($sb)
+
+            $content = $sb.ToString()
+
+            Write-Host $content.Replace("&$", "&``$")
+
+            $content | Should -Be "# :x: Build failure :x:
+
+Build result: [Failed](/_build/index?buildId=)
+
 [comment]: <> (This is a test result report added by Azure DevOps)
 "
         }

tools/devops/automation/scripts/TestResults.psm1

@@ -247,6 +247,7 @@ class TestResult {
 }
 
 class ParallelTestsResults {
+    [string] $BuildFailureMessage
     [string] $Context
     [string] $TestPrefix
     [string] $VSDropsIndex
@@ -264,6 +265,12 @@ class ParallelTestsResults {
         $this.VSDropsIndex = $vsDropsIndex
     }
 
+    ParallelTestsResults (
+        [string] $buildFailureMessage
+    ) {
+        $this.BuildFailureMessage = $buildFailureMessage
+    }
+
     [object] GetFailingTests() {
         $failingTests = [System.Collections.ArrayList]@()
         foreach ($result in $this.Results) {
@@ -285,6 +292,9 @@ class ParallelTestsResults {
     }
 
     [bool] IsSuccess() {
+        if (-not [string]::IsNullOrEmpty($this.BuildFailureMessage)) {
+            return $false
+        }
         $failingTests = $this.GetFailingTests()
         return $failingTests.Count -eq 0
     }
@@ -332,6 +342,16 @@ class ParallelTestsResults {
     }
 
     [void] WriteComment($stringBuilder) {
+        if (-not [string]::IsNullOrEmpty($this.BuildFailureMessage)) {
+            $pipelineLink = "$Env:SYSTEM_TEAMFOUNDATIONCOLLECTIONURI$Env:SYSTEM_TEAMPROJECT/_build/index?buildId=$Env:BUILD_BUILDID"
+            $stringBuilder.AppendLine("# :x: Build failure :x:")
+            $stringBuilder.AppendLine()
+            $stringBuilder.AppendLine("Build result: [$($this.BuildFailureMessage)]($($pipelineLink))")
+            $stringBuilder.AppendLine()
+            $stringBuilder.AppendLine("[comment]: <> (This is a test result report added by Azure DevOps)")
+            return
+        }
+
         $stringBuilder.AppendLine("# Test results")
         # We need to add a small summary at the top. We check if it was a success, if that is
         # the case, we just need to state it and
@@ -458,6 +478,13 @@ function New-ParallelTestsResults {
 
     $stageDep = $StageDependencies | ConvertFrom-Json -AsHashtable
 
+    $buildResult = $stageDep.build_macos_tests.build_macos_tests_job.result
+    Write-Host "Build result: $buildResult"
+    if ($buildResult -ne "Succeeded") {
+        Write-Host "Build did not succeed: $buildResult"
+        return [ParallelTestsResults]::new($buildResult)
+    }
+
     $matrix = $stageDep.configure_build.configure.outputs["test_matrix.TEST_MATRIX"] | ConvertFrom-Json -AsHashtable
     $suites = [System.Collections.SortedList]::new()
     foreach ($title in $matrix.Keys) {