diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5976a772..b11c1d65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -30,6 +30,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 - **Tests**: `UserResourceTest.createUser` checks that GET after delete returns 404. `UserResourceIntegrationTest` no longer repeats that create and delete on a real server ([#313](https://github.com/sitmun/sitmun-backend-core/issues/313)).
 - **Tests**: `ServiceCheckStoreTest`, `AffectedApplicationsTest`, `ServiceHealthFilterTest`, `ServiceAccessSummaryTest`, and `ServiceCheckDispatcherTest` load `ServiceCheckSliceConfiguration` on the suite database, so Liquibase runs once for that slice. Connections do not autocommit, so the transactional slice removes its rows ([#317](https://github.com/sitmun/sitmun-backend-core/issues/317)).
 - **Tests**: `AuthenticationControllerLdapEnabledTest` starts the in-memory LDAP directory once for the class. The role-lookup case still returns HTTP 401 and no cookie only when `LdapUserAuthoritiesPopulator` rejects the user ([#319](https://github.com/sitmun/sitmun-backend-core/issues/319)).
+- **Tests**: A JDBC URL `jdbc:h2:mem:testdb;MODE=NOT_A_MODE` is rejected with an SQLException that names the unknown mode. `POST /api/connections/test` returns HTTP 400 for that URL. `GET /api/connections/{id}/test` no longer repeats the same rejection ([#314](https://github.com/sitmun/sitmun-backend-core/issues/314)).
 - **Tests**: Database connection, role, territory, territory group type, and user repository tests use MockMvc on the shared context. They no longer boot an embedded server ([#316](https://github.com/sitmun/sitmun-backend-core/issues/316)).
 
 ### Security
diff --git a/src/test/java/org/sitmun/administration/controller/DatabaseConnectionControllerTest.java b/src/test/java/org/sitmun/administration/controller/DatabaseConnectionControllerTest.java
index 59cab147..3406d404 100644
--- a/src/test/java/org/sitmun/administration/controller/DatabaseConnectionControllerTest.java
+++ b/src/test/java/org/sitmun/administration/controller/DatabaseConnectionControllerTest.java
@@ -1,5 +1,6 @@
 package org.sitmun.administration.controller;
 
+import static org.hamcrest.Matchers.containsString;
 import static org.mockito.Mockito.when;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
 import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.post;
@@ -32,24 +33,6 @@ void failIfDatabaseConnectionDriverNotFound() throws Exception {
         .andExpect(jsonPath("$.message").value("java.lang.ClassNotFoundException: org.h2.DriverX"));
   }
 
-  @Test
-  @WithMockUser(roles = "ADMIN")
-  @DisplayName("GET returns 400 when the JDBC URL has no driver")
-  void failIfDatabaseConnectionException() throws Exception {
-    when(repository.findById(0))
-        .thenReturn(
-            Optional.of(
-                DatabaseConnection.builder()
-                    .driver("org.h2.Driver")
-                    .url("jdb:h2:mem:testdb")
-                    .name("sa")
-                    .password("password")
-                    .build()));
-    mvc.perform(get("/api/connections/0/test"))
-        .andExpect(status().isBadRequest())
-        .andExpect(jsonPath("$.message").value("No suitable driver found for jdb:h2:mem:testdb"));
-  }
-
   @Test
   @WithMockUser(roles = "ADMIN")
   @DisplayName("GET returns valid true")
@@ -106,15 +89,15 @@ void failPostTestIfDatabaseConnectionDriverNotFound() throws Exception {
 
   @Test
   @WithMockUser(roles = "ADMIN")
-  @DisplayName("POST returns 400 when the JDBC URL has no driver")
+  @DisplayName("POST returns 400 when the JDBC URL is malformed")
   void failPostTestIfDatabaseConnectionException() throws Exception {
     mvc.perform(
             post("/api/connections/test")
                 .contentType(MediaType.APPLICATION_JSON)
                 .content(
-                    "{ \"driver\" : \"org.h2.Driver\", \"url\" : \"jdb:h2:mem:testdb\", \"user\" : \"sa\", \"password\" : null }"))
+                    "{ \"driver\" : \"org.h2.Driver\", \"url\" : \"jdbc:h2:mem:testdb;MODE=NOT_A_MODE\", \"user\" : \"sa\", \"password\" : null }"))
         .andExpect(status().isBadRequest())
-        .andExpect(jsonPath("$.message").value("No suitable driver found for jdb:h2:mem:testdb"));
+        .andExpect(jsonPath("$.message", containsString("Unknown mode \"NOT_A_MODE\"")));
   }
 
   @Test
diff --git a/src/test/java/org/sitmun/administration/service/database/tester/DatabaseConnectionTesterServiceTest.java b/src/test/java/org/sitmun/administration/service/database/tester/DatabaseConnectionTesterServiceTest.java
index d4753a82..e8c46769 100644
--- a/src/test/java/org/sitmun/administration/service/database/tester/DatabaseConnectionTesterServiceTest.java
+++ b/src/test/java/org/sitmun/administration/service/database/tester/DatabaseConnectionTesterServiceTest.java
@@ -73,11 +73,12 @@ void malformedJdbcUrlThrowsSqlException() {
     DatabaseConnection connection =
         DatabaseConnection.builder()
             .driver("org.h2.Driver")
-            .url("jdb:h2:mem:testdb")
+            .url("jdbc:h2:mem:testdb;MODE=NOT_A_MODE")
             .user("sa")
             .password(null)
             .build();
     sut.testDriver(connection);
-    assertThrows(SQLException.class, () -> sut.testConnection(connection));
+    SQLException exception = assertThrows(SQLException.class, () -> sut.testConnection(connection));
+    assertTrue(exception.getMessage().contains("Unknown mode \"NOT_A_MODE\""));
   }
 }