Merge pull request #727 from KyleAure/ensure-yassonParser-implements-all-API

test: ensure YassonParser implements JsonParser default methods

src/test/java/org/eclipse/yasson/internal/deserializer/YassonParserTest.java

diff --git a/src/test/java/org/eclipse/yasson/internal/deserializer/YassonParserTest.java b/src/test/java/org/eclipse/yasson/internal/deserializer/YassonParserTest.java
new file mode 100644
index 0000000..c12787a
--- /dev/null
+++ b/src/test/java/org/eclipse/yasson/internal/deserializer/YassonParserTest.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2026 IBM and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0,
+ * or the Eclipse Distribution License v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+
+package org.eclipse.yasson.internal.deserializer;
+
+import org.junit.jupiter.api.Test;
+
+import jakarta.json.stream.JsonParser;
+
+import static org.junit.jupiter.api.Assertions.fail;
+
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.List;
+
+
+/**
+ * The {@link jakarta.json.stream.JsonParser} interface has optional methods that 
+ * throw default UnsupportedOperationExceptions, but that must be implemented in
+ * order to pass the JSON-P TCK.  Since the YassonParser wraps a JsonParser we 
+ * must ensure that we implement these default methods and we cannot rely on the
+ * compiler to tell us if we missed one so this test will.
+ */
+public class YassonParserTest {
+
+    @Test
+    public void overrideDefaultMethodTest() {
+        List<Method> expectedMethods = Arrays.asList(JsonParser.class.getMethods());
+        
+        for(Method expectedMethod : expectedMethods) {
+            if(!expectedMethod.isDefault()) {
+                continue; //compiler will catch if we fail to implement
+            }
+
+            try {
+                YassonParser.class.getDeclaredMethod(expectedMethod.getName(), expectedMethod.getParameterTypes());
+            } catch (NoSuchMethodException e) {
+                fail("Expected YassonParser to override " + expectedMethod.getName() 
+                        + " but instead got " + e.getMessage());
+            }
+        }
+    }
+}