diff --git a/tests/attempt_ui/question_ui_renderer_test.php b/tests/attempt_ui/question_ui_renderer_test.php
index 5335a09..5f95859 100644
--- a/tests/attempt_ui/question_ui_renderer_test.php
+++ b/tests/attempt_ui/question_ui_renderer_test.php
@@ -19,13 +19,17 @@
 defined('MOODLE_INTERNAL') || die();
 
 global $CFG;
+require_once($CFG->dirroot . '/question/engine/tests/helpers.php');
 require_once($CFG->dirroot . '/question/type/questionpy/question.php');
 
 use coding_exception;
 use PHPUnit\Framework\MockObject\Stub;
 use qtype_questionpy\api\api;
+use qtype_questionpy\constants;
 use qtype_questionpy_question;
 use question_attempt;
+use question_attempt_step;
+use testable_question_attempt;
 
 /**
  * Unit tests for {@see question_ui_renderer}.
@@ -80,7 +84,7 @@ public function test_should_hide_inline_feedback(): void {
         <div xmlns="http://www.w3.org/1999/xhtml">
             <span>No feedback</span>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -104,7 +108,7 @@ public function test_should_show_inline_feedback(): void {
             <span>General feedback</span>
             <span>Specific feedback</span>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -122,27 +126,27 @@ public function test_should_mangle_names(): void {
         $result = $ui->render();
 
         $this->assert_html_string_equals_html_string(<<<EXPECTED
-        <div xmlns="http://www.w3.org/1999/xhtml" id="mangled:my_div">
-            <datalist id="mangled:my_list">
+        <div xmlns="http://www.w3.org/1999/xhtml" id="q1:1_my_div">
+            <datalist id="q1:1_my_list">
                 <option>42</option>
             </datalist>
-            <label>Wrapping label <input class="form-control qpy-input" name="mangled:my_number"
-                                         type="number" list="mangled:my_list"/></label>
-            <label for="mangled:my_select">Separate label</label>
-            <select class="form-control qpy-input" id="mangled:my_select" name="mangled:my_select">
+            <label>Wrapping label <input class="form-control qpy-input" name="q1:1_my_number"
+                                         type="number" list="q1:1_my_list"/></label>
+            <label for="q1:1_my_select">Separate label</label>
+            <select class="form-control qpy-input" id="q1:1_my_select" name="q1:1_my_select">
                 <option value="1">One</option>
                 <option value="2">Two</option>
             </select>
-            <input class="qpy-input" type="radio" name="mangled:my_radio" value="1"/>
-            <input class="qpy-input" type="radio" name="mangled:my_radio" value="2"/>
-            <textarea class="form-control qpy-input" name="mangled:my_text"/>
-            <button class="btn btn-primary qpy-input" name="mangled:my_button">Click me!</button>
-            <map name="mangled:my_map">
+            <input class="qpy-input" type="radio" name="q1:1_my_radio" value="1"/>
+            <input class="qpy-input" type="radio" name="q1:1_my_radio" value="2"/>
+            <textarea class="form-control qpy-input" name="q1:1_my_text"/>
+            <button class="btn btn-primary qpy-input" name="q1:1_my_button">Click me!</button>
+            <map name="q1:1_my_map">
                 <area shape="circle" coords="1, 2, 3"/>
             </map>
-            <img src="https://picsum.photos/200/300" usemap="#mangled:my_map"/>
+            <img src="https://picsum.photos/200/300" usemap="#q1:1_my_map"/>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -179,7 +183,7 @@ public function test_should_shuffle_correctly_and_replace_indices(): void {
                 </div>
             </div>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -195,7 +199,7 @@ public function test_should_shuffle_the_same_way_in_same_attempt(): void {
         $firstresult = (new question_ui_renderer($input, [], new \question_display_options(), $qa))->render();
         for ($i = 0; $i < 10; $i++) {
             $result = (new question_ui_renderer($input, [], new \question_display_options(), $qa))->render();
-            $this->assertEquals($firstresult, $result);
+            $this->assertEquals($firstresult->html, $result->html);
         }
     }
 
@@ -225,7 +229,7 @@ public function test_should_resolve_placeholders(): void {
             <span>Plain parameter: Value of param &lt;b>one&lt;/b>.&lt;script>'Oh no, danger!'&lt;/script>
             </span>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -257,7 +261,7 @@ public function test_should_correctly_handle_broken_html_in_placeholder_expansio
             <span>Noclean parameter: <format-float>123</format-float><unknown-tag></unknown-tag><div>unclosed</div></span>
             <span>Plain parameter: &lt;qpy:format-float>123&lt;/qpy:format-float>&lt;unknown-tag>&lt;/unknown-tag>&lt;div>unclosed</span>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
         // phpcs:enable moodle.Files.LineLength.TooLong
     }
 
@@ -283,7 +287,7 @@ public function test_should_remove_placeholders_when_no_corresponding_value(): v
             <span>Noclean parameter: </span>
             <span>Plain parameter: </span>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -312,7 +316,7 @@ public function test_should_soften_validations(): void {
                    data-qpy_minlength="5" data-qpy_maxlength="10"
                    aria-valuemin="17" data-qpy_min="17" aria-valuemax="42" data-qpy_max="42"/>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -338,7 +342,7 @@ public function test_should_defuse_buttons(): void {
             <input class="btn btn-primary qpy-input" type="button" value="Reset"/>
             <input class="btn btn-primary qpy-input" type="button" value="Button"/>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -363,7 +367,7 @@ public function test_should_remove_element_with_if_role_attribute(): void {
 
         $this->assert_html_string_equals_html_string(<<<EXPECTED
         <div xmlns="http://www.w3.org/1999/xhtml"></div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -395,7 +399,7 @@ public function test_should_not_remove_element_with_if_role_attribute(): void {
             <div>You're a proctor!</div>
             <div>You're any of the above!</div>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -421,7 +425,7 @@ public function test_should_format_floats_in_en(): void {
             Pad with zeros: 1.10000
             Strip zeros: 1.1
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -444,7 +448,7 @@ public function test_should_replace_qpy_urls(): void {
             static link: <a href="https://www.example.com/moodle/pluginfile.php//qtype_questionpy/static/deadbeef/local/minimal_example/path1/path2/filename.txt">https://www.example.com/moodle/pluginfile.php//qtype_questionpy/static/deadbeef/local/minimal_example/path1/path2/filename.txt</a>
             minimal path: <a href="https://www.example.com/moodle/pluginfile.php//qtype_questionpy/static/deadbeef/local/minimal_example/f">https://www.example.com/moodle/pluginfile.php//qtype_questionpy/static/deadbeef/local/minimal_example/f</a>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
         // phpcs:enable moodle.Files.LineLength.MaxExceeded
     }
 
@@ -457,8 +461,7 @@ public function test_should_replace_qpy_urls(): void {
      */
     public function test_should_correctly_fill_data(): void {
         $input = file_get_contents(__DIR__ . '/question_uis/input-values.xhtml');
-        $qa = $this->create_question_attempt_stub('deadbeef');
-        $newvalues = [
+        $qa = $this->create_question_attempt_stub('deadbeef', lastresponse: [
             'my_text' => 'new',
             'my_checkbox_value' => 'value',
             'my_checkbox_on' => 'on',
@@ -466,35 +469,33 @@ public function test_should_correctly_fill_data(): void {
             'my_select' => 'value3',
             'my_hidden' => 'new',
             'my_button' => 'should be ignored',
-        ];
-        $qa->method('get_last_qt_var')
-            ->willReturnCallback(fn($name) => $newvalues[$name]);
+        ]);
 
         $ui = new question_ui_renderer($input, [], new \question_display_options(), $qa);
         $result = $ui->render();
 
         $this->assert_html_string_equals_html_string(<<<EXPECTED
-        <div xmlns="http://www.w3.org/1999/xhtml" id="mangled:my_div">
-            <input class="form-control qpy-input" type="text" name="mangled:my_text" value="new"/>
+        <div xmlns="http://www.w3.org/1999/xhtml" id="q1:1_my_div">
+            <input class="form-control qpy-input" type="text" name="q1:1_my_text" value="new"/>
 
-            <input class="qpy-input" type="checkbox" name="mangled:my_checkbox_value" value="value" checked="checked"/>
-            <input class="qpy-input" type="checkbox" name="mangled:my_checkbox_on" checked="checked"/>
+            <input class="qpy-input" type="checkbox" name="q1:1_my_checkbox_value" value="value" checked="checked"/>
+            <input class="qpy-input" type="checkbox" name="q1:1_my_checkbox_on" checked="checked"/>
 
-            <input class="qpy-input" type="radio" name="mangled:my_radio" value="value1" checked="checked"/>
-            <input class="qpy-input" type="radio" name="mangled:my_radio" value="value2"/>
+            <input class="qpy-input" type="radio" name="q1:1_my_radio" value="value1" checked="checked"/>
+            <input class="qpy-input" type="radio" name="q1:1_my_radio" value="value2"/>
 
-            <select class="form-control qpy-input" name="mangled:my_select">
+            <select class="form-control qpy-input" name="q1:1_my_select">
                 <option value="value1"/>
                 <option value="value2"/>
                 <option value="value3" selected="selected"/>
             </select>
 
-            <input class="form-control qpy-input" type="hidden" name="mangled:my_hidden" value="new"/>
+            <input class="form-control qpy-input" type="hidden" name="q1:1_my_hidden" value="new"/>
 
-            <input class="btn btn-primary qpy-input" name="mangled:my_button" type="button" value="value1"/>
-            <input class="btn btn-primary qpy-input" name="mangled:my_button" type="button" value="value2"/>
+            <input class="btn btn-primary qpy-input" name="q1:1_my_button" type="button" value="value1"/>
+            <input class="btn btn-primary qpy-input" name="q1:1_my_button" type="button" value="value2"/>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -506,23 +507,23 @@ public function test_should_correctly_fill_data(): void {
      */
     public function test_should_add_fallback_option_to_select_when_value_isnt_present(): void {
         $input = file_get_contents(__DIR__ . '/question_uis/select.xhtml');
-        $qa = $this->create_question_attempt_stub('deadbeef');
-        $qa->method('get_last_qt_var')
-            ->willReturn('something');
+        $qa = $this->create_question_attempt_stub('deadbeef', lastresponse: [
+            'my_select' => 'something',
+        ]);
 
         $ui = new question_ui_renderer($input, [], new \question_display_options(), $qa);
         $result = $ui->render();
 
         $this->assert_html_string_equals_html_string(<<<EXPECTED
         <div xmlns="http://www.w3.org/1999/xhtml" >
-            <select class="form-control qpy-input" name="mangled:my_select">
+            <select class="form-control qpy-input" name="q1:1_my_select">
                 <option value="value1"/>
                 <option value="value2"/>
                 <option value="value3"/>
                 <option value="something" selected="selected">(the selected option is no longer available)</option>
             </select>
         </div>
-        EXPECTED, $result);
+        EXPECTED, $result->html);
     }
 
     /**
@@ -531,21 +532,23 @@ public function test_should_add_fallback_option_to_select_when_value_isnt_presen
      * @param string|null $packagehash explicit package hash. Random if unset.
      * @param int|null $id explicit attempt database id. Random if unset.
      * @return question_attempt&Stub
+     * @throws coding_exception
      */
-    private function create_question_attempt_stub(?string $packagehash = null, ?int $id = null): question_attempt {
+    private function create_question_attempt_stub(?string $packagehash = null, ?int $id = null,
+                                                  array $lastresponse = []): question_attempt {
         $packagehash ??= hash('sha256', random_string(64));
         $id ??= mt_rand();
         $question = new qtype_questionpy_question($packagehash, '{}', null, $this->createStub(api::class));
 
-        $qa = $this->createStub(question_attempt::class);
-        $qa->method('get_database_id')
-            ->willReturn($id);
-        $qa->method('get_question')
-            ->willReturn($question);
-        $qa->method('get_qt_field_name')
-            ->willReturnCallback(function ($name) {
-                return "mangled:$name";
-            });
+        $step = new question_attempt_step(array_merge($lastresponse, [
+            constants::QT_VAR_RESPONSE_MARKER => '',
+        ]));
+
+        $qa = new testable_question_attempt($question, 1);
+        $qa->set_database_id($id);
+        $qa->set_slot(1);
+        $qa->add_step($step);
+
         return $qa;
     }
 }