This commit is related to BAEL-7331 (#15624)

This commit aims to add a new test class "DeprecatedJsonParserUnitTest".

json-modules/gson-2/src/test/java/com/baeldung/gson/deprecatedjsonparser/DeprecatedJsonParserUnitTest.java

@@ -0,0 +1,42 @@
+package com.baeldung.deprecatedjsonparser;
+
+import com.google.gson.JsonObject;
+import com.google.gson.JsonParser;
+import com.google.gson.stream.JsonReader;
+import org.junit.jupiter.api.Test;
+
+import java.io.StringReader;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class DeprecatedJsonParserUnitTest {
+
+    String jsonString = "{\"name\": \"John\", \"age\":30, \"city\":\"New York\"}";
+    JsonObject expectedJsonObject = new JsonObject();
+
+    DeprecatedJsonParserUnitTest() {
+        expectedJsonObject.addProperty("name", "John");
+        expectedJsonObject.addProperty("age", 30);
+        expectedJsonObject.addProperty("city", "New York");
+    }
+
+    @Test
+    public void givenJsonString_whenUsingParseString_thenJsonObjectIsExpected() {
+        JsonObject jsonObjectAlt = JsonParser.parseString(jsonString).getAsJsonObject();
+        assertEquals(expectedJsonObject, jsonObjectAlt);
+    }
+
+    @Test
+    public void givenJsonString_whenUsingParseReader_thenJsonObjectIsExpected() {
+        StringReader reader = new StringReader(jsonString);
+        JsonObject jsonObject = JsonParser.parseReader(reader).getAsJsonObject();
+        assertEquals(expectedJsonObject, jsonObject);
+    }
+
+    @Test
+    public void givenJsonReader_whenParseUsingJsonReader_thenJsonObjectIsExpected() {
+        JsonReader jsonReader = new JsonReader(new StringReader(jsonString));
+        JsonObject jsonObject = JsonParser.parseReader(jsonReader).getAsJsonObject();
+        assertEquals(expectedJsonObject, jsonObject);
+    }
+}