Test: lock fputcsv enum field Error parity (#5898)

test/compliance/cases/stdlib/fputcsv_enum_field.phpt

@@ -0,0 +1,25 @@
+--TEST--
+stdlib fputcsv() enum field → Error like Zend (#5898, ext/standard/file.c)
+--FILE--
+<?php
+enum E: string { case A = 'a'; }
+$fp = fopen('php://memory', 'r+');
+try {
+    $n = fputcsv($fp, [E::A]);
+    rewind($fp);
+    echo 'n=', $n, ' line=', stream_get_contents($fp), "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp);
+$fp2 = fopen('php://memory', 'r+');
+try {
+    fputcsv($fp2, [E::A]);
+    echo "void_ok\n";
+} catch (Throwable $e) {
+    echo 'void:', get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp2);
+--EXPECT--
+Error: Object of class E could not be converted to string
+void:Error: Object of class E could not be converted to string

test/compliance/cases/stdlib/fputcsv_enum_field_jit.phpt

@@ -0,0 +1,24 @@
+--TEST--
+stdlib fputcsv() enum field → Error like Zend JIT (#5898, ext/standard/file.c)
+--FILE--
+<?php
+enum E: string { case A = 'a'; }
+$fp = fopen('php://memory', 'r+');
+try {
+    $n = fputcsv($fp, [E::A]);
+    echo 'n=', $n, "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp);
+$fp2 = fopen('php://memory', 'r+');
+try {
+    fputcsv($fp2, [E::A]);
+    echo "void_ok\n";
+} catch (Throwable $e) {
+    echo 'void:', get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp2);
+--EXPECT--
+Error: Object of class E could not be converted to string
+void:Error: Object of class E could not be converted to string

test/repro/issue_5898_fputcsv_enum_field.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Issue #5898 — fputcsv() enum field must Error like Zend (ext/standard/file.c).
+ */
+enum E: string
+{
+    case A = 'a';
+}
+
+$fp = fopen('php://memory', 'r+');
+try {
+    $n = fputcsv($fp, [E::A]);
+    rewind($fp);
+    echo 'n=', $n, ' line=', stream_get_contents($fp), "\n";
+} catch (Throwable $e) {
+    echo get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp);
+
+$fp2 = fopen('php://memory', 'r+');
+try {
+    fputcsv($fp2, [E::A]);
+    echo "void_ok\n";
+} catch (Throwable $e) {
+    echo 'void:', get_class($e), ': ', $e->getMessage(), PHP_EOL;
+}
+fclose($fp2);