Test that expected implementation is actually used

test/functional/backends/test_netssh_scp.rb

@@ -12,6 +12,12 @@ def setup
           ssh.transfer_method = :scp
         end
       end
+
+      def test_scp_implementation_is_used
+        Netssh.new(a_host).send(:with_transfer, nil) do |transfer|
+          assert_instance_of Netssh::ScpTransfer, transfer
+        end
+      end
     end
   end
 end

test/functional/backends/test_netssh_sftp.rb

@@ -12,6 +12,12 @@ def setup
           ssh.transfer_method = :sftp
         end
       end
+
+      def test_sftp_implementation_is_used
+        Netssh.new(a_host).send(:with_transfer, nil) do |transfer|
+          assert_instance_of Netssh::SftpTransfer, transfer
+        end
+      end
     end
   end
 end

test/unit/backends/test_netssh.rb

@@ -5,6 +5,12 @@ module SSHKit
   module Backend
     class TestNetssh < UnitTest
 
+      def teardown
+        super
+        # Reset config to defaults after each test
+        backend.instance_variable_set :@config, nil
+      end
+
       def backend
         @backend ||= Netssh
       end
@@ -41,6 +47,26 @@ def test_transfer_method_prohibits_invalid_values
         assert_match ":nope is not a valid transfer method", error.message
       end
 
+      def test_transfer_method_defaults_to_scp
+        assert_equal :scp, backend.config.transfer_method
+      end
+
+      def test_host_can_override_transfer_method
+        backend.configure do |ssh|
+          ssh.transfer_method = :scp
+        end
+
+        host = Host.new("fake")
+        host.transfer_method = :sftp
+
+        netssh = backend.new(host)
+        netssh.stubs(:with_ssh).yields(nil)
+
+        netssh.send(:with_transfer, nil) do |transfer|
+          assert_instance_of Netssh::SftpTransfer, transfer
+        end
+      end
+
       def test_netssh_ext
         assert_includes  Net::SSH::Config.default_files, "#{Dir.pwd}/.ssh/config"
       end