Add validation to winrm shell type option

Signed-off-by: Catriona Malone <[email protected]>

lib/train-winrm/transport.rb

@@ -46,6 +46,7 @@ class Transport < Train.plugin(1) # rubocop:disable Metrics/ClassLength
 
       # ref: https://github.com/winrb/winrm#transports
       SUPPORTED_WINRM_TRANSPORTS = %i{negotiate ssl plaintext kerberos}.freeze
+      SUPPORTED_WINRM_SHELL_TYPES = %i{powershell elevated cmd}.freeze
 
       # common target configuration
       option :host, required: true
@@ -106,6 +107,11 @@ def validate_options(opts)
           raise Train::ClientError, "Unsupported transport type: #{winrm_transport.inspect}"
         end
 
+        winrm_shell_type = opts[:winrm_shell_type].to_sym
+        unless SUPPORTED_WINRM_SHELL_TYPES.include?(winrm_shell_type)
+          raise Train::ClientError, "Unsupported winrm shell type: #{winrm_shell_type.inspect}"
+        end
+
         # remove leading '/'
         path = (opts[:path] || "").sub(%r{^/+}, "")