tests: add 12 DB persistence functional tests, rebalance groups

Add backend-agnostic functional tests for database message persistence.
All tests work with both SQLite and flat-file backends.

New tests in test_history.c:
- message_db_history_on_reopen: basic incoming write+read round-trip
- message_db_history_multiple: 3 messages from different resources
- message_db_history_contact_isolation: buddy1 msg absent from buddy2
- message_db_history_special_chars: XML entities survive DB round-trip
- message_db_history_outgoing: sent message persists across reopen
- message_db_history_dialog: outgoing + incoming both in history
- message_db_history_empty: no crash on contact with no history
- message_db_history_long_message: 1000+ char body not truncated
- message_db_history_newline: embedded LF stored correctly
- message_db_history_service_chars: backslash pipe percent braces etc
- message_db_history_verify: /history verify reports no issues
- message_db_history_lmc: XEP-0308 correction replaces original in DB

Rebalance test groups for parallel execution (19/23/22/21):
- Group 1: Connect, Ping, Rooms, Software, LastActivity
- Group 2: Message, Receipts, Roster, DB History
- Group 3: Chat Session, Presence, Disconnect
- Group 4: MUC, Carbons

tests/functionaltests/functionaltests.c

@@ -15,10 +15,10 @@
  * functional tests run less frequently than unit tests.
  *
  * Tests are organized into groups for better maintainability and parallel execution:
- *   Group 1: Connect, Ping, Rooms, Software
- *   Group 2: Message, Receipts, Roster, Chat Session
- *   Group 3: Presence, Disconnect
- *   Group 4: MUC, Carbons
+ *   Group 1: Connect, Ping, Rooms, Software, Last Activity  (19 tests)
+ *   Group 2: Message, Receipts, Roster, DB History           (23 tests)
+ *   Group 3: Chat Session, Presence, Disconnect              (22 tests)
+ *   Group 4: MUC, Carbons                                    (21 tests)
  *
  * Parallel execution:
  *   ./functionaltests        - run all tests sequentially
@@ -53,6 +53,7 @@
 #include "test_muc.h"
 #include "test_disconnect.h"
 #include "test_lastactivity.h"
+#include "test_history.h"
 
 /* Macro to wrap each test with setup/teardown functions */
 #define PROF_FUNC_TEST(test) cmocka_unit_test_setup_teardown(test, init_prof_test, close_prof_test)
@@ -77,8 +78,9 @@ main(int argc, char* argv[])
     fprintf(stderr, "[PROF_TEST] Starting functional tests, group=%d\n", group);
 
     /* ============================================================
-     * GROUP 1: Connect, Ping, Rooms, Software
+     * GROUP 1: Connect, Ping, Rooms, Software, Last Activity
      * Basic XMPP session establishment and server queries
+     * (19 tests)
      * ============================================================ */
     const struct CMUnitTest group1_tests[] = {
         /* Connection tests - verify login, roster, bookmarks */
@@ -112,8 +114,9 @@ main(int argc, char* argv[])
     };
 
     /* ============================================================
-     * GROUP 2: Message, Receipts, Roster, Chat Session
+     * GROUP 2: Message, Receipts, Roster, DB History
      * Core messaging and contact management
+     * (23 tests)
      * ============================================================ */
     const struct CMUnitTest group2_tests[] = {
         /* Basic message send/receive */
@@ -133,6 +136,27 @@ main(int argc, char* argv[])
         PROF_FUNC_TEST(sends_remove_item_nick),
         PROF_FUNC_TEST(sends_nick_change),
 
+        /* Database persistence - message write+read round-trip */
+        PROF_FUNC_TEST(message_db_history_on_reopen),
+        PROF_FUNC_TEST(message_db_history_multiple),
+        PROF_FUNC_TEST(message_db_history_contact_isolation),
+        PROF_FUNC_TEST(message_db_history_special_chars),
+        PROF_FUNC_TEST(message_db_history_outgoing),
+        PROF_FUNC_TEST(message_db_history_dialog),
+        PROF_FUNC_TEST(message_db_history_empty),
+        PROF_FUNC_TEST(message_db_history_long_message),
+        PROF_FUNC_TEST(message_db_history_newline),
+        PROF_FUNC_TEST(message_db_history_service_chars),
+        PROF_FUNC_TEST(message_db_history_verify),
+        PROF_FUNC_TEST(message_db_history_lmc),
+    };
+
+    /* ============================================================
+     * GROUP 3: Chat Session, Presence, Disconnect
+     * Session routing, status management, clean teardown
+     * (22 tests)
+     * ============================================================ */
+    const struct CMUnitTest group3_tests[] = {
         /* Chat session management - bare/full JID routing */
         PROF_FUNC_TEST(sends_message_to_barejid_when_contact_offline),
         PROF_FUNC_TEST(sends_message_to_barejid_when_contact_online),
@@ -140,13 +164,8 @@ main(int argc, char* argv[])
         PROF_FUNC_TEST(sends_subsequent_messages_to_fulljid),
         PROF_FUNC_TEST(resets_to_barejid_after_presence_received),
         PROF_FUNC_TEST(new_session_when_message_received_from_different_fulljid),
-    };
 
-    /* ============================================================
-     * GROUP 3: Presence, Disconnect
-     * Online/away/xa/dnd/chat status management
-     * ============================================================ */
-    const struct CMUnitTest group3_tests[] = {
+        /* Presence - online/away/xa/dnd/chat status management */
         PROF_FUNC_TEST(presence_online),
         PROF_FUNC_TEST(presence_online_with_message),
         PROF_FUNC_TEST(presence_away),
@@ -170,6 +189,7 @@ main(int argc, char* argv[])
     /* ============================================================
      * GROUP 4: MUC, Carbons
      * Multi-user chat and message synchronization
+     * (21 tests)
      * ============================================================ */
     const struct CMUnitTest group4_tests[] = {
         /* MUC room join with various options - XEP-0045 */
@@ -212,9 +232,9 @@ main(int argc, char* argv[])
         const struct CMUnitTest* tests;
         size_t count;
     } groups[] = {
-        { "Group 1: Connect/Ping/Rooms/Software", group1_tests, ARRAY_SIZE(group1_tests) },
-        { "Group 2: Message/Receipts/Roster/Session", group2_tests, ARRAY_SIZE(group2_tests) },
-        { "Group 3: Presence/Disconnect", group3_tests, ARRAY_SIZE(group3_tests) },
+        { "Group 1: Connect/Ping/Rooms/Software/LastActivity", group1_tests, ARRAY_SIZE(group1_tests) },
+        { "Group 2: Message/Receipts/Roster/DBHistory", group2_tests, ARRAY_SIZE(group2_tests) },
+        { "Group 3: Session/Presence/Disconnect", group3_tests, ARRAY_SIZE(group3_tests) },
         { "Group 4: MUC/Carbons", group4_tests, ARRAY_SIZE(group4_tests) },
     };
     const int num_groups = ARRAY_SIZE(groups);