Issue #3496287 by nevergone: Test "Hide previous value" feature

tests/src/Functional/TestLockPreviousValue.php

+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\Tests\field_lock_multi_values\Functional;
+
+use PHPUnit\Framework\Attributes\Group;
+
+/**
+ * Generic test base class.
+ */
+#[Group('field_lock_multi_values')]
+class TestLockPreviousValue extends TestBase {
+
+  public function testLockPreviousValue() {
+    $page = $this->getSession()->getPage();
+    // Submit a test node.
+    $delta = 4;
+    $this->drupalGet('/node/add/page');
+    for ($i = 0; $i < $delta; $i++) {
+      $this->submitForm([], 'Add another item');
+    }
+    $edit = [
+      'edit-title-0-value' => $this->randomMachineName(),
+    ];
+    for ($i = 0; $i <= $delta; $i++) {
+      $edit["{$this->field_id}[$i][value]"] = $this->randomMachineName();
+      $edit["{$this->field_id}[$i][_weight]"] = $i;
+
+    }
+    $this->submitForm($edit, 'Save');
+    // Test node edit form with original functionality.
+    $this->drupalGet('/node/1/edit');
+    for ($i = 0; $i <= $delta; $i++) {
+      $disabled = $page->findById("edit-field-string-textfield-$i-value")
+        ->getAttribute('disabled');
+      $this->assertEquals('', $disabled);
+    }
+    // TODO: check!
+    // enable "Lock Previous Value" feature.
+    $this->drupalGet('/admin/structure/types/manage/page/form-display');
+    $this->click('#edit-fields-field-string-textfield-settings-edit');
+    $page->checkField('Lock previous value');
+    $this->submitForm([], 'Update');
+    $this->submitForm([], 'Save');
+    // Test node edit form with updated functionality.
+    $this->drupalGet('/node/1/edit');
+    for ($i = 0; $i <= $delta; $i++) {
+      $disabled = $page->findById("edit-field-string-textfield-$i-value")
+        ->getAttribute('disabled');
+      $this->assertEquals('disabled', $disabled);
+    }
+  }
+}