add serialization tests

Author: David Motsonashvili

firebase-ai/src/test/java/com/google/firebase/ai/SerializationTests.kt

@@ -16,6 +16,8 @@
 
 package com.google.firebase.ai
 
+import com.google.firebase.ai.common.TemplateGenerateContentRequest
+import com.google.firebase.ai.common.TemplateGenerateImageRequest
 import com.google.firebase.ai.common.util.descriptorToJson
 import com.google.firebase.ai.type.Candidate
 import com.google.firebase.ai.type.CountTokensResponse
@@ -512,6 +514,56 @@ internal class SerializationTests {
     expectedJsonAsString shouldEqualJson actualJson.toString()
   }
 
+    @Test
+    fun `test template request serialization as Json`() {
+        val expectedJsonAsString =
+            """
+        {
+          "id": "TemplateGenerateContentRequest",
+          "type": "object",
+          "properties": {
+            "inputs": {
+              "type": "object",
+              "additionalProperties": {
+                "${"$"}ref": "JsonElement"
+              }
+            },
+            "history": {
+              "type": "array",
+              "items": {
+                "${"$"}ref": "Content"
+              }
+            }
+          }
+        }
+      """
+                .trimIndent()
+        val actualJson = descriptorToJson(TemplateGenerateContentRequest.serializer().descriptor)
+        expectedJsonAsString shouldEqualJson actualJson.toString()
+    }
+
+    @Test
+    fun `test template imagen request serialization as Json`() {
+        val expectedJsonAsString =
+            """
+        {
+          "id": "TemplateGenerateImageRequest",
+          "type": "object",
+          "properties": {
+            "inputs": {
+              "type": "object",
+              "additionalProperties": {
+                "${"$"}ref": "JsonElement"
+              }
+            }
+          }
+        }
+      """
+                .trimIndent()
+        val actualJson = descriptorToJson(TemplateGenerateImageRequest.serializer().descriptor)
+        expectedJsonAsString shouldEqualJson actualJson.toString()
+    }
+
   @Test
   fun `test GoogleSearch serialization as Json`() {
     val expectedJsonAsString =