feat: Add pattern matching test for JsonValue

Author: simbo1905

src/test/java/jdk/sandbox/internal/util/json/JsonPatternMatchingTests.java

@@ -0,0 +1,50 @@
+package jdk.sandbox.internal.util.json;
+
+import jdk.sandbox.java.util.json.JsonArray;
+import jdk.sandbox.java.util.json.JsonBoolean;
+import jdk.sandbox.java.util.json.JsonNull;
+import jdk.sandbox.java.util.json.JsonNumber;
+import jdk.sandbox.java.util.json.JsonObject;
+import jdk.sandbox.java.util.json.JsonString;
+import jdk.sandbox.java.util.json.JsonValue;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class JsonPatternMatchingTests {
+
+    private String identifyJsonValue(JsonValue jsonValue) {
+        return switch (jsonValue) {
+            case JsonObject o -> "Object with " + o.members().size() + " members";
+            case JsonArray a -> "Array with " + a.values().size() + " elements";
+            case JsonString s -> "String with value: " + s.value();
+            case JsonNumber n -> "Number with value: " + n.toNumber();
+            case JsonBoolean b -> "Boolean with value: " + b.value();
+            case JsonNull ignored -> "Null";
+        };
+    }
+
+    @Test
+    void testPatternMatchingOnJsonTypes() {
+        String json = """
+        {
+            "myObject": {},
+            "myArray": [1, 2],
+            "myString": "hello",
+            "myNumber": 123.45,
+            "myBoolean": true,
+            "myNull": null
+        }
+        """;
+
+        JsonParser parser = new JsonParser(json.toCharArray());
+        JsonObject jsonObject = (JsonObject) parser.parseRoot();
+
+        assertThat(identifyJsonValue(jsonObject.members().get("myObject"))).isEqualTo("Object with 0 members");
+        assertThat(identifyJsonValue(jsonObject.members().get("myArray"))).isEqualTo("Array with 2 elements");
+        assertThat(identifyJsonValue(jsonObject.members().get("myString"))).isEqualTo("String with value: hello");
+        assertThat(identifyJsonValue(jsonObject.members().get("myNumber"))).isEqualTo("Number with value: 123.45");
+        assertThat(identifyJsonValue(jsonObject.members().get("myBoolean"))).isEqualTo("Boolean with value: true");
+        assertThat(identifyJsonValue(jsonObject.members().get("myNull"))).isEqualTo("Null");
+    }
+}