diff --git a/app/src/test/java/com/m57/hermescontrol/ui/chat/ChatPersistenceRepositoryTest.kt b/app/src/test/java/com/m57/hermescontrol/ui/chat/ChatPersistenceRepositoryTest.kt
new file mode 100644
index 00000000..57a3e7ae
--- /dev/null
+++ b/app/src/test/java/com/m57/hermescontrol/ui/chat/ChatPersistenceRepositoryTest.kt
@@ -0,0 +1,113 @@
+package com.m57.hermescontrol.ui.chat
+
+import com.m57.hermescontrol.ui.chat.fakes.FakeChatMessageDao
+import kotlinx.coroutines.test.runTest
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+
+class ChatPersistenceRepositoryTest {
+    private lateinit var dao: FakeChatMessageDao
+    private lateinit var repository: ChatPersistenceRepository
+
+    @Before
+    fun setup() {
+        dao = FakeChatMessageDao()
+        repository = ChatPersistenceRepository(dao)
+    }
+
+    @Test
+    fun persistMessage_upsertsToDao() =
+        runTest {
+            val sessionId = "session-1"
+            val message =
+                ChatMessage(
+                    id = "msg-1",
+                    role = MessageRole.USER,
+                    content = "Hello, world!",
+                    timestamp = 1000L,
+                )
+
+            repository.persistMessage(message, sessionId)
+
+            val daoMessages = dao.getMessagesForSession(sessionId)
+            assertEquals(1, daoMessages.size)
+            val entity = daoMessages.first()
+            assertEquals("msg-1", entity.id)
+            assertEquals(sessionId, entity.sessionId)
+            assertEquals("USER", entity.role)
+            assertEquals("Hello, world!", entity.content)
+            assertEquals(1000L, entity.timestamp)
+        }
+
+    @Test
+    fun persistMessages_upsertsAllToDao() =
+        runTest {
+            val sessionId = "session-2"
+            val messages =
+                listOf(
+                    ChatMessage(id = "msg-2", role = MessageRole.SYSTEM, content = "System msg", timestamp = 2000L),
+                    ChatMessage(id = "msg-3", role = MessageRole.ASSISTANT, content = "Response", timestamp = 3000L),
+                )
+
+            repository.persistMessages(messages, sessionId)
+
+            val daoMessages = dao.getMessagesForSession(sessionId)
+            assertEquals(2, daoMessages.size)
+
+            assertEquals("msg-2", daoMessages[0].id)
+            assertEquals(sessionId, daoMessages[0].sessionId)
+            assertEquals("SYSTEM", daoMessages[0].role)
+            assertEquals("System msg", daoMessages[0].content)
+            assertEquals(2000L, daoMessages[0].timestamp)
+
+            assertEquals("msg-3", daoMessages[1].id)
+            assertEquals(sessionId, daoMessages[1].sessionId)
+            assertEquals("ASSISTANT", daoMessages[1].role)
+            assertEquals("Response", daoMessages[1].content)
+            assertEquals(3000L, daoMessages[1].timestamp)
+        }
+
+    @Test
+    fun loadMessages_returnsMappedMessagesFromDao() =
+        runTest {
+            val sessionId = "session-3"
+            val message1 = ChatMessage(id = "msg-4", role = MessageRole.USER, content = "Q", timestamp = 4000L)
+            val message2 = ChatMessage(id = "msg-5", role = MessageRole.ASSISTANT, content = "A", timestamp = 5000L)
+
+            repository.persistMessages(listOf(message1, message2), sessionId)
+
+            val loadedMessages = repository.loadMessages(sessionId)
+            assertEquals(2, loadedMessages.size)
+            assertEquals("msg-4", loadedMessages[0].id)
+            assertEquals(MessageRole.USER, loadedMessages[0].role)
+            assertEquals("Q", loadedMessages[0].content)
+
+            assertEquals("msg-5", loadedMessages[1].id)
+            assertEquals(MessageRole.ASSISTANT, loadedMessages[1].role)
+            assertEquals("A", loadedMessages[1].content)
+        }
+
+    @Test
+    fun loadMessages_filtersBySessionId() =
+        runTest {
+            val sessionA = "session-A"
+            val sessionB = "session-B"
+            val messageA1 = ChatMessage(id = "msg-A1", role = MessageRole.USER, content = "Hi A", timestamp = 1000L)
+            val messageB1 = ChatMessage(id = "msg-B1", role = MessageRole.USER, content = "Hi B", timestamp = 2000L)
+            val messageB2 =
+                ChatMessage(id = "msg-B2", role = MessageRole.ASSISTANT, content = "Hello B", timestamp = 3000L)
+
+            repository.persistMessage(messageA1, sessionA)
+            repository.persistMessages(listOf(messageB1, messageB2), sessionB)
+
+            val loadedA = repository.loadMessages(sessionA)
+            assertEquals(1, loadedA.size)
+            assertEquals("msg-A1", loadedA[0].id)
+
+            val loadedB = repository.loadMessages(sessionB)
+            assertEquals(2, loadedB.size)
+            assertEquals("msg-B1", loadedB[0].id)
+            assertEquals("msg-B2", loadedB[1].id)
+        }
+}