From 7c80bf2ffc968d9824c0c39b4d5639d8f529d133 Mon Sep 17 00:00:00 2001
From: Arnold Galovics <galovicsarnold@gmail.com>
Date: Mon, 24 Jul 2023 14:44:23 +0200
Subject: [PATCH] FINERACT-1724: Client search API fix when external ID is null

---
 .../converter/ExternalIdJsonConverter.java    |  2 ++
 .../client/ClientSearchTest.java              | 26 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/fineract-provider/src/main/java/org/apache/fineract/infrastructure/core/jersey/converter/ExternalIdJsonConverter.java b/fineract-provider/src/main/java/org/apache/fineract/infrastructure/core/jersey/converter/ExternalIdJsonConverter.java
index b8e089d65..054715163 100644
--- a/fineract-provider/src/main/java/org/apache/fineract/infrastructure/core/jersey/converter/ExternalIdJsonConverter.java
+++ b/fineract-provider/src/main/java/org/apache/fineract/infrastructure/core/jersey/converter/ExternalIdJsonConverter.java
@@ -42,6 +42,8 @@ public class ExternalIdJsonConverter implements JsonConverter<ExternalId> {
     public void convertToJson(ExternalId value, JsonGenerator generator) throws IOException {
         if (value != null && !value.isEmpty()) {
             generator.writeString(value.getValue());
+        } else {
+            generator.writeNull();
         }
     }
 
diff --git a/integration-tests/src/test/java/org/apache/fineract/integrationtests/client/ClientSearchTest.java b/integration-tests/src/test/java/org/apache/fineract/integrationtests/client/ClientSearchTest.java
index e37908f7d..5d26ed4cb 100644
--- a/integration-tests/src/test/java/org/apache/fineract/integrationtests/client/ClientSearchTest.java
+++ b/integration-tests/src/test/java/org/apache/fineract/integrationtests/client/ClientSearchTest.java
@@ -73,6 +73,32 @@ public class ClientSearchTest {
         assertThat(result.getTotalPages()).isEqualTo(3);
     }
 
+    @Test
+    public void testClientSearchWorks_WhenNoExternalIdForClients() {
+        // given
+        String lastname = Utils.randomStringGenerator("Client_LastName_", 5);
+        PostClientsRequest request1 = ClientHelper.defaultClientCreationRequest();
+        request1.setExternalId(null);
+        request1.setLastname(lastname);
+        clientHelper.createClient(request1);
+
+        PostClientsRequest request2 = ClientHelper.defaultClientCreationRequest();
+        request2.setExternalId(null);
+        request2.setLastname(lastname);
+        clientHelper.createClient(request2);
+
+        PostClientsRequest request3 = ClientHelper.defaultClientCreationRequest();
+        request3.setExternalId(null);
+        request3.setLastname(lastname);
+        clientHelper.createClient(request3);
+        // when
+        PageClientSearchData result = clientHelper.searchClients(lastname, 0, 1);
+        // then
+        assertThat(result.getTotalElements()).isEqualTo(3);
+        assertThat(result.getNumberOfElements()).isEqualTo(1);
+        assertThat(result.getTotalPages()).isEqualTo(3);
+    }
+
     @Test
     public void testClientSearchWorks_WithLastnameTextOnDefaultOrdering() {
         // given