fix test helpers

test/CMakeLists.txt

@@ -24,10 +24,10 @@ endforeach()
 # $1 exec, $2 input, $3 output_result
 if(WIN32)
 FILE(WRITE ${CMAKE_CURRENT_BINARY_DIR}/test_helper.ps1
-"Remove-Item -Force $args[2]\n"
+"if (Test-Path $args[2]) { Remove-Item -Force $args[2] } \n"
 "$ErrorActionPreference = \"Stop\"\n"
 "Get-Content $args[1] | & $args[0]\n"
-"If (Get-Content $args[2] | %{$_ -match \"FATAL\"}) {\n"
+"If ((Get-Content $args[2] | %{$_ -match \"FATAL\"}) -contains $true) {\n"
 "echo Error\n"
 "exit 1\n"
 "} else {\n"