TW-1718: Test for "String UDA not passed through unchanged"

test/tw-1718.t

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+. bash_tap_tw.sh
+
+echo "uda.foo.label=foo" >> taskrc
+echo "uda.foo.type=string" >> taskrc
+
+# This sets foo to "PT13H" despite it being a string UDA
+task add bar foo:"3h+10h"
+
+# Show the problem in TAP output
+task _get 1.foo
+
+task _get 1.foo | grep '3h+10h'