Handle error and retry test results push.

tools/appveyor.psm1

@@ -36,8 +36,39 @@ function Update-AppVeyorTestResults
 
     if($env:Appveyor)
     {
+        $retryCount = 0 
+        $pushedResults = $false
+        $pushedArtifacts = $false 
+        while( (!$pushedResults -or !$pushedResults) -and $retryCount -lt 3)
+        {
+            if($retryCount -gt 0)
+            {
+                Write-Verbose "Retrying updating test artifacts..."
+            }
+
+            $retryCount++
             $resolvedResultsPath = (Resolve-Path $resultsFile)
+            try {
                 (New-Object 'System.Net.WebClient').UploadFile("https://ci.appveyor.com/api/testresults/nunit/$($env:APPVEYOR_JOB_ID)", $resolvedResultsPath)
+                $pushedResults = $true
+            }
+            catch {
+                Write-Warning "Pushing test result failed..."
+            }
+
+            try {
+                Push-AppveyorArtifact $resolvedResultsPath
+                $pushedArtifacts = $true
+            }
+            catch {
+                Write-Warning "Pushing test Artifact failed..."
+            }
+        }
+        
+        if(!$pushedResults -or !$pushedResults)
+        {
+            Write-Warning "Failed to push all artifacts for $resultsFile"
+        }
     }
     else 
     {