tests: Windows: run commands through explicit bash & temp shell script

Makes some of the commands work on Windows where system is cmd.exe

tests/test.d/simple_test.rb

@@ -324,7 +324,7 @@ class SimpleTest
     puts "COMMAND #{command}" if ENV['DEBUG']
 
     exit_code = 0
-    if !system(command)
+    if !run_bash command
       exit_code = $? >> 8
       self.error "system command failed: #{command} (#{exit_code})" if options[:exit_code] != exit_code
     end

tests/test.d/test.rb

@@ -65,7 +65,10 @@ class Test
     command         << " >/dev/null 2>/dev/null " unless (/>/.match(command))
 
     puts "COMMAND #{command}" if ENV['DEBUG']
-    error "system command failed: #{command} (" + ($? >> 8).to_s + ")" if !system(command) && ((arg.size == 0) || ((arg[0] << 8) != $?))
+
+    result = run_bash command
+
+    error "system command failed: #{command} (" + ($? >> 8).to_s + ")" if !result && ((arg.size == 0) || ((arg[0] << 8) != $?))
   end
 
   def tmp_name_prefix

tests/test.d/util.rb

@@ -51,3 +51,15 @@ else
     `md5sum #{name}`.chomp.gsub(/\s+.*/, "")
   end
 end
+
+def run_bash command
+  return system command if !$is_windows
+
+  cmd_file = Tempfile.new
+  cmd_file.write command
+  cmd_file.close
+
+  FileUtils.chmod 0700, cmd_file.path
+
+  system "bash -c #{cmd_file.path}"
+end