diff --git a/ext/dom/tests/DOMProcessingInstruction.phpt b/ext/dom/tests/DOMProcessingInstruction.phpt
new file mode 100644
index 00000000000..ca79e31966e
--- /dev/null
+++ b/ext/dom/tests/DOMProcessingInstruction.phpt
@@ -0,0 +1,87 @@
+--TEST--
+Tests for DOMProcessingInstruction class
+--EXTENSIONS--
+dom
+--FILE--
+<?php
+
+class FailingStringable {
+    public function __toString(): string {
+        throw new Exception("failed in __toString");
+    }
+}
+
+echo "--- Test construction ---\n";
+
+try {
+    $pi = new DOMProcessingInstruction("\0");
+} catch (DOMException $e) {
+    echo $e->getMessage(), "\n";
+}
+
+$pi = new DOMProcessingInstruction("test");
+
+echo "--- Test fields ---\n";
+
+var_dump($pi->target);
+var_dump($pi->data);
+$pi->data = "ok";
+var_dump($pi->data);
+try {
+    $pi->data = new FailingStringable;
+} catch (Throwable $e) {
+    echo $e->getMessage(), "\n";
+}
+var_dump($pi->data);
+$pi->data = 12345;
+var_dump($pi->data);
+$pi->data = "my data <>";
+var_dump($pi->data);
+
+echo "--- Test appending ---\n";
+
+$doc = new DOMDocument;
+$doc->appendChild($doc->createElement('root'));
+$doc->documentElement->appendChild($doc->adoptNode($pi));
+echo $doc->saveXML();
+
+echo "--- Test construction with __construct by reflection and fields ---\n";
+
+$class = new ReflectionClass('DOMProcessingInstruction');
+$instance = $class->newInstanceWithoutConstructor();
+
+try {
+    var_dump($instance->target);
+} catch (Throwable $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    var_dump($instance->data);
+} catch (Throwable $e) {
+    echo $e->getMessage(), "\n";
+}
+try {
+    $instance->data = "hello";
+} catch (Throwable $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+--- Test construction ---
+Invalid Character Error
+--- Test fields ---
+string(4) "test"
+string(0) ""
+string(2) "ok"
+failed in __toString
+string(2) "ok"
+string(5) "12345"
+string(10) "my data <>"
+--- Test appending ---
+<?xml version="1.0"?>
+<root><?test my data <>?></root>
+--- Test construction with __construct by reflection and fields ---
+Invalid State Error
+Invalid State Error
+Invalid State Error