Implement a feature test for :hint all userscript.

This adds a (testdata) substitution for 'When I run {command}' to allow
providing an absolute path for the userscript.

tests/integration/data/userscripts/echo_hint_text

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+echo "message-info '$QUTE_SELECTED_TEXT'" >> "$QUTE_FIFO"

tests/integration/features/conftest.py

@@ -128,6 +128,7 @@ def run_command(quteproc, httpbin, command):
     else:
         count = None
     command = command.replace('(port)', str(httpbin.port))
+    command = command.replace('(testdata)', utils.abs_datapath())
 
     quteproc.send_cmd(command, count=count)
 

tests/integration/features/hints.feature

@@ -75,6 +75,13 @@ Feature: Using hints
         And I press the key "<Enter>"
         Then the message "http://localhost:(port)/data/hello.txt" should be shown
 
+    @posix
+    Scenario: Using :hint userscript
+        When I open data/hints/html/simple.html
+        And I run :hint all userscript (testdata)/userscripts/echo_hint_text
+        And I run :follow-hint a
+        Then the message "Follow me!" should be shown
+
     Scenario: Yanking to primary selection without it being supported (#1336)
         When selection is not supported
         And I run :debug-set-fake-clipboard