Add more tests

Author: StefanScherer

golang-issue-18555/test.ps1

@@ -1,2 +1,10 @@
 Write-Host Testing new golang image to build on volume mountpoint
+Write-Host The webserver dir before running the go build:
+dir ..\webserver
 docker run -v "$(pwd)\..\webserver:C:\code" -w /code golang-issue-18555 go build webserver.go
+Write-Host Current dir after running the go build:
+Write-Host The webserver dir after running the go build:
+dir ..\webserver
+if (!(Test-Path ..\webserver\webserver.exe)) {
+  Write-Error webserver.exe is missing, go build didn't work in container
+}