BAEL-2037 - Code for mini-article (#4923)

* BAEL-2037 - Code for mini-article

* BAEL-2037 - Fixes after editors review

* Fixing dependencies

* Change File Reader

* Formatting

* Fix imports

* Rename test class

json/src/test/java/com/baeldung/jsonpointer/JsonPointerCrudUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.jsonpointer;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class JsonPointerCrudUnitTest {
+
+    @Test
+    public void testJsonPointerCrudForAddress() {
+
+        JsonPointerCrud jsonPointerCrud = new JsonPointerCrud(JsonPointerCrudUnitTest.class.getResourceAsStream("/address.json"));
+
+        assertFalse(jsonPointerCrud.check("city"));
+
+        // insert a value
+        jsonPointerCrud.insert("city", "Rio de Janeiro");
+
+        assertTrue(jsonPointerCrud.check("city"));
+
+        // fetch full json
+        String fullJSON = jsonPointerCrud.fetchFullJSON();
+
+        assertTrue(fullJSON.contains("name"));
+
+        assertTrue(fullJSON.contains("city"));
+
+        // fetch value
+        String cityName = jsonPointerCrud.fetchValueFromKey("city");
+
+        assertEquals(cityName, "Rio de Janeiro");
+
+        // update value
+        jsonPointerCrud.update("city", "Sao Paulo");
+
+        // fetch value
+        cityName = jsonPointerCrud.fetchValueFromKey("city");
+
+        assertEquals(cityName, "Sao Paulo");
+
+        // delete
+        jsonPointerCrud.delete("city");
+
+        assertFalse(jsonPointerCrud.check("city"));
+
+    }
+
+    @Test
+    public void testJsonPointerCrudForBooks() {
+
+        JsonPointerCrud jsonPointerCrud = new JsonPointerCrud(JsonPointerCrudUnitTest.class.getResourceAsStream("/books.json"));
+
+        // fetch value
+        String book = jsonPointerCrud.fetchListValues("books/1");
+
+        assertEquals(book, "{\"title\":\"Title 2\",\"author\":\"John Doe\"}");
+
+    }
+}