BAEL-2147 Kotlin Data Class from Json using GSON (#5220)

* BAEL-1846: Java Image to Base64 String

* Move from using main method to Junit test

* Update to use environment variables for testing

* reformat and add test file

* spring boot jsp security taglibs

* add more test

* add more test

* refactor spring config

* refactor spring config

* Update README.md

* fi alignment

* fix requested comments

* additional tests and content

* additional tests and content

* update examples

* Delete Readme file

* edit form example

* adding example for spring boot security tag libs

* Remove old tag libs module

* BAEL-2147 Add GsonTest

* BAEL-2147 Remove unused import

core-kotlin/src/test/kotlin/com/baeldung/kotlin/gson/GsonUnitTest.kt

@@ -0,0 +1,30 @@
+package com.baeldung.kotlin.gson
+
+import com.google.gson.Gson
+
+import org.junit.Assert
+import org.junit.Test
+
+class GsonUnitTest {
+
+    var gson = Gson()
+
+    @Test
+    fun givenObject_thenGetJSONString() {
+        var jsonString = gson.toJson(TestModel(1,"Test"))
+        Assert.assertEquals(jsonString, "{\"id\":1,\"description\":\"Test\"}")
+    }
+
+    @Test
+    fun givenJSONString_thenGetObject() {
+        var jsonString = "{\"id\":1,\"description\":\"Test\"}";
+        var testModel = gson.fromJson(jsonString, TestModel::class.java)
+        Assert.assertEquals(testModel.id, 1)
+        Assert.assertEquals(testModel.description, "Test")
+    }
+
+    data class TestModel(
+        val id: Int,
+        val description: String
+    )
+}