test: AssertsToolErrors helper for tool error assertions (T3)

tests/Support/AssertsToolErrors (used by TestCase): assertToolError($result, code)
checks the WP_Error code lit_<code> and the code of the client JSON and returns the
payload; clientError() decodes the payload; errorFields() returns the fields and
asserts they exist. Replaces the private clientError() decoders of
DiviWriteAbilitiesTest/DiviReplaceTextAbilityTest, 216 single-line
assertSame('lit_…', …->get_error_code()) assertions, 24 get_error_data()['fields']
digs and two json_decode(message) reads. ErrorsTest keeps json_decode: it tests
the format itself. Tests 1404 -> 1409 (AssertsToolErrorsTest); no test has fewer
assertions.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/Unit/Integrations/WordPress/Revisions/RevisionRestoreAbilityTest.php

@@ -50,7 +50,7 @@ final class RevisionRestoreAbilityTest extends TestCase
 
     public function testNonRevisionIdIsNotFound(): void
     {
-        self::assertSame('lit_not_found', $this->ability(FakeChangeLog::forbidden())->permission(['revision_id' => 5])->get_error_code());
+        self::assertToolError($this->ability(FakeChangeLog::forbidden())->permission(['revision_id' => 5]), 'not_found');
     }
 
     public function testRequiresConfirmation(): void
@@ -59,7 +59,7 @@ final class RevisionRestoreAbilityTest extends TestCase
 
         $result = $this->ability(FakeChangeLog::forbidden())->execute(['revision_id' => 810]);
 
-        self::assertSame('lit_confirm_required', $result->get_error_code());
+        self::assertToolError($result, 'confirm_required');
     }
 
     public function testOrphanRevisionYieldsValidationErrorOnRevisionIdField(): void
@@ -71,8 +71,8 @@ final class RevisionRestoreAbilityTest extends TestCase
         $error = $this->ability(FakeChangeLog::forbidden())
             ->permission(['revision_id' => 810, 'rev' => 'irrelevant', 'confirm' => true]);
 
-        self::assertSame('lit_validation_failed', $error->get_error_code());
-        self::assertArrayHasKey('revision_id', $error->get_error_data()['fields']);
+        self::assertToolError($error, 'validation_failed');
+        self::assertArrayHasKey('revision_id', self::errorFields($error));
     }
 
     public function testATrashedEntryIsRefused(): void
@@ -86,8 +86,8 @@ final class RevisionRestoreAbilityTest extends TestCase
 
         $error = $this->ability(FakeChangeLog::forbidden())->execute(['revision_id' => 810, 'rev' => 'x', 'confirm' => true]);
 
-        self::assertSame('lit_validation_failed', $error->get_error_code());
-        self::assertArrayHasKey('revision_id', $error->get_error_data()['fields']);
+        self::assertToolError($error, 'validation_failed');
+        self::assertArrayHasKey('revision_id', self::errorFields($error));
     }
 
     public function testAMissedScheduleIsRefusedBecauseRestoringWouldPublish(): void
@@ -110,7 +110,7 @@ final class RevisionRestoreAbilityTest extends TestCase
             'confirm' => true,
         ]);
 
-        self::assertSame('lit_validation_failed', $error->get_error_code());
+        self::assertToolError($error, 'validation_failed');
         self::assertStringContainsString('lit-post-publish', $error->get_error_data()['hint']);
     }
 
@@ -121,7 +121,7 @@ final class RevisionRestoreAbilityTest extends TestCase
         $result = $this->ability(FakeChangeLog::forbidden())
             ->execute(['revision_id' => 810, 'confirm' => true, 'rev' => 'stale']);
 
-        self::assertSame('lit_rev_mismatch', $result->get_error_code());
+        self::assertToolError($result, 'rev_mismatch');
     }
 
     public function testSavesTheCurrentStateThenRestores(): void
@@ -173,7 +173,7 @@ final class RevisionRestoreAbilityTest extends TestCase
             'rev' => $this->currentRev(),
         ]);
 
-        self::assertSame('lit_write_failed', $result->get_error_code());
+        self::assertToolError($result, 'write_failed');
         self::assertStringNotContainsString('Nichts wurde gespeichert', $result->get_error_message());
         self::assertStringContainsString(
             'Die Änderung wurde nicht gespeichert (Revision 813 bleibt erhalten).',

tests/Unit/Integrations/WordPress/Revisions/RevisionsListAbilityTest.php

@@ -79,6 +79,6 @@ final class RevisionsListAbilityTest extends TestCase
     {
         $result = $this->ability()->execute(['post_id' => 5, 'cursor' => 'not-a-cursor']);
 
-        self::assertSame('lit_validation_failed', $result->get_error_code());
+        self::assertToolError($result, 'validation_failed');
     }
 }