diff --git a/testcases/t/226-internal-workspaces.t b/testcases/t/226-internal-workspaces.t
new file mode 100644
index 00000000..a73445fb
--- /dev/null
+++ b/testcases/t/226-internal-workspaces.t
@@ -0,0 +1,65 @@
+#!perl
+# vim:ts=4:sw=4:expandtab
+#
+# Please read the following documents before working on tests:
+# • http://build.i3wm.org/docs/testsuite.html
+#   (or docs/testsuite)
+#
+# • http://build.i3wm.org/docs/lib-i3test.html
+#   (alternatively: perldoc ./testcases/lib/i3test.pm)
+#
+# • http://build.i3wm.org/docs/ipc.html
+#   (or docs/ipc)
+#
+# • http://onyxneon.com/books/modern_perl/modern_perl_a4.pdf
+#   (unless you are already familiar with Perl)
+#
+# Verifies that internal workspaces (those whose name starts with __) cannot be
+# used in all commands that deal with workspaces.
+# Ticket: #1209
+# Bug still in: 4.7.2-154-g144e3fb
+use i3test i3_autostart => 0;
+
+sub internal_workspaces {
+    scalar grep { /^__/ } @{get_workspace_names()}
+}
+
+my $config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+EOT
+
+my $pid = launch_with_config($config);
+
+is(internal_workspaces(), 0, 'No internal workspaces');
+
+cmd 'workspace __foo';
+is(internal_workspaces(), 0, 'No internal workspaces');
+
+cmd 'move to workspace __foo';
+is(internal_workspaces(), 0, 'No internal workspaces');
+
+cmd 'rename workspace to __foo';
+is(internal_workspaces(), 0, 'No internal workspaces');
+
+exit_gracefully($pid);
+
+################################################################################
+# Verify that new workspace names starting with __ are ignored.
+################################################################################
+
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+
+bindsym Mod1+1 workspace __foo
+bindsym Mod1+2 workspace bar
+EOT
+
+$pid = launch_with_config($config);
+
+is_deeply(get_workspace_names(), [ 'bar' ], 'New workspace called bar, not __foo');
+
+exit_gracefully($pid);
+
+done_testing;