test: add edge-case tests for CRDT sync correctness and error handling

Add 7 new SQLite unit tests and 7 new PostgreSQL test files covering:
  - DWS/AWS algorithm rejection (unsupported CRDT algos return clean errors)
  - Corrupted payload handling (empty, garbage, truncated, bit-flipped)
  - Payload apply idempotency (3x apply produces identical results)
  - Causal-length tie-breaking determinism (3-way concurrent update convergence)
  - Delete/resurrect with out-of-order payload delivery
  - Large composite primary key (5-column mixed-type PK roundtrip)
  - PostgreSQL-specific type roundtrips (JSONB, TIMESTAMPTZ, NUMERIC, BYTEA)
  - Schema hash mismatch detection (ALTER TABLE without cloudsync workflow)

Author: andinux

test/postgresql/40_unsupported_algorithms.sql

@@ -0,0 +1,80 @@
+-- Test unsupported CRDT algorithms (DWS, AWS)
+-- Verifies that cloudsync_init rejects DWS and AWS with clear errors
+-- and that no metadata tables are created.
+
+\set testid '40'
+\ir helper_test_init.sql
+
+\connect postgres
+\ir helper_psql_conn_setup.sql
+DROP DATABASE IF EXISTS cloudsync_test_40;
+CREATE DATABASE cloudsync_test_40;
+
+\connect cloudsync_test_40
+\ir helper_psql_conn_setup.sql
+CREATE EXTENSION IF NOT EXISTS cloudsync;
+
+CREATE TABLE test_dws (id TEXT PRIMARY KEY, val TEXT);
+CREATE TABLE test_aws (id TEXT PRIMARY KEY, val TEXT);
+
+-- Test DWS rejection
+DO $$
+BEGIN
+  PERFORM cloudsync_init('test_dws', 'dws', true);
+  RAISE EXCEPTION 'cloudsync_init with dws should have failed';
+EXCEPTION WHEN OTHERS THEN
+  IF SQLERRM NOT LIKE '%not yet supported%' THEN
+    RAISE EXCEPTION 'Unexpected error for dws: %', SQLERRM;
+  END IF;
+END $$;
+
+-- Verify no companion table was created for DWS
+SELECT COUNT(*) = 0 AS no_dws_meta
+FROM information_schema.tables
+WHERE table_name = 'test_dws_cloudsync' \gset
+\if :no_dws_meta
+\echo [PASS] (:testid) DWS rejected - no metadata table created
+\else
+\echo [FAIL] (:testid) DWS metadata table should not exist
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Test AWS rejection
+DO $$
+BEGIN
+  PERFORM cloudsync_init('test_aws', 'aws', true);
+  RAISE EXCEPTION 'cloudsync_init with aws should have failed';
+EXCEPTION WHEN OTHERS THEN
+  IF SQLERRM NOT LIKE '%not yet supported%' THEN
+    RAISE EXCEPTION 'Unexpected error for aws: %', SQLERRM;
+  END IF;
+END $$;
+
+-- Verify no companion table was created for AWS
+SELECT COUNT(*) = 0 AS no_aws_meta
+FROM information_schema.tables
+WHERE table_name = 'test_aws_cloudsync' \gset
+\if :no_aws_meta
+\echo [PASS] (:testid) AWS rejected - no metadata table created
+\else
+\echo [FAIL] (:testid) AWS metadata table should not exist
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Verify CLS still works (sanity check)
+SELECT cloudsync_init('test_dws', 'cls', true) AS _init_cls \gset
+SELECT COUNT(*) = 1 AS cls_meta_ok
+FROM information_schema.tables
+WHERE table_name = 'test_dws_cloudsync' \gset
+\if :cls_meta_ok
+\echo [PASS] (:testid) CLS init works after DWS/AWS rejection
+\else
+\echo [FAIL] (:testid) CLS init should work
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Cleanup
+\ir helper_test_cleanup.sql
+\if :should_cleanup
+DROP DATABASE IF EXISTS cloudsync_test_40;
+\endif

test/postgresql/41_corrupted_payload.sql

@@ -0,0 +1,126 @@
+-- Test corrupted payload handling
+-- Verifies that cloudsync_payload_apply rejects corrupted payloads
+-- without crashing or corrupting state.
+
+\set testid '41'
+\ir helper_test_init.sql
+
+\connect postgres
+\ir helper_psql_conn_setup.sql
+DROP DATABASE IF EXISTS cloudsync_test_41_src;
+DROP DATABASE IF EXISTS cloudsync_test_41_dst;
+CREATE DATABASE cloudsync_test_41_src;
+CREATE DATABASE cloudsync_test_41_dst;
+
+-- Setup source database with data
+\connect cloudsync_test_41_src
+\ir helper_psql_conn_setup.sql
+CREATE EXTENSION IF NOT EXISTS cloudsync;
+CREATE TABLE test_tbl (id TEXT PRIMARY KEY, val TEXT);
+SELECT cloudsync_init('test_tbl', 'CLS', true) AS _init_src \gset
+INSERT INTO test_tbl VALUES ('id1', 'value1');
+INSERT INTO test_tbl VALUES ('id2', 'value2');
+
+-- Get a valid payload
+SELECT encode(cloudsync_payload_encode(tbl, pk, col_name, col_value, col_version, db_version, site_id, cl, seq), 'hex') AS valid_payload_hex
+FROM cloudsync_changes
+WHERE site_id = cloudsync_siteid() \gset
+
+-- Setup destination database
+\connect cloudsync_test_41_dst
+\ir helper_psql_conn_setup.sql
+CREATE EXTENSION IF NOT EXISTS cloudsync;
+CREATE TABLE test_tbl (id TEXT PRIMARY KEY, val TEXT);
+SELECT cloudsync_init('test_tbl', 'CLS', true) AS _init_dst \gset
+
+-- Record initial state
+SELECT COUNT(*) AS initial_count FROM test_tbl \gset
+
+-- Test 1: Empty blob (zero bytes)
+DO $$
+BEGIN
+  PERFORM cloudsync_payload_apply(''::bytea);
+  -- If it returns without error with 0 rows, that's also acceptable
+EXCEPTION WHEN OTHERS THEN
+  -- Expected: error on empty payload
+  NULL;
+END $$;
+
+SELECT COUNT(*) AS count_after_empty FROM test_tbl \gset
+SELECT (:count_after_empty::int = :initial_count::int) AS empty_blob_ok \gset
+\if :empty_blob_ok
+\echo [PASS] (:testid) Empty blob rejected - table unchanged
+\else
+\echo [FAIL] (:testid) Empty blob corrupted table state
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Test 2: Random garbage bytes
+DO $$
+BEGIN
+  PERFORM cloudsync_payload_apply(decode('deadbeefcafebabe0102030405060708', 'hex'));
+EXCEPTION WHEN OTHERS THEN
+  -- Expected: error on garbage payload
+  NULL;
+END $$;
+
+SELECT COUNT(*) AS count_after_garbage FROM test_tbl \gset
+SELECT (:count_after_garbage::int = :initial_count::int) AS garbage_ok \gset
+\if :garbage_ok
+\echo [PASS] (:testid) Garbage bytes rejected - table unchanged
+\else
+\echo [FAIL] (:testid) Garbage bytes corrupted table state
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Test 3: Truncated payload (first 10 bytes of valid payload)
+-- Build truncated hex at top level using psql variable interpolation
+SELECT substr(:'valid_payload_hex', 1, 20) AS truncated_hex \gset
+SELECT cloudsync_payload_apply(decode(:'truncated_hex', 'hex')) AS _apply_truncated \gset
+-- If the above errors, psql continues (ON_ERROR_STOP is off)
+
+SELECT COUNT(*) AS count_after_truncated FROM test_tbl \gset
+SELECT (:count_after_truncated::int = :initial_count::int) AS truncated_ok \gset
+\if :truncated_ok
+\echo [PASS] (:testid) Truncated payload rejected - table unchanged
+\else
+\echo [FAIL] (:testid) Truncated payload corrupted table state
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Test 4: Valid payload with flipped byte in the middle
+-- Compute corrupted payload at top level: flip one byte via XOR with FF
+SELECT
+  substr(:'valid_payload_hex', 1, length(:'valid_payload_hex') / 2 - 1)
+  || lpad(to_hex(get_byte(decode(substr(:'valid_payload_hex', length(:'valid_payload_hex') / 2, 2), 'hex'), 0) # 255), 2, '0')
+  || substr(:'valid_payload_hex', length(:'valid_payload_hex') / 2 + 2)
+  AS corrupted_hex \gset
+SELECT cloudsync_payload_apply(decode(:'corrupted_hex', 'hex')) AS _apply_corrupted \gset
+-- If the above errors, psql continues (ON_ERROR_STOP is off)
+
+SELECT COUNT(*) AS count_after_flipped FROM test_tbl \gset
+SELECT (:count_after_flipped::int = :initial_count::int) AS flipped_ok \gset
+\if :flipped_ok
+\echo [PASS] (:testid) Flipped-byte payload rejected - table unchanged
+\else
+\echo [FAIL] (:testid) Flipped-byte payload corrupted table state
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Test 5: Now apply the VALID payload to confirm it still works
+SELECT cloudsync_payload_apply(decode(:'valid_payload_hex', 'hex')) AS valid_apply \gset
+SELECT COUNT(*) AS count_after_valid FROM test_tbl \gset
+SELECT (:count_after_valid::int = 2) AS valid_ok \gset
+\if :valid_ok
+\echo [PASS] (:testid) Valid payload applied successfully after corrupted attempts
+\else
+\echo [FAIL] (:testid) Valid payload failed after corrupted attempts - count: :count_after_valid
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Cleanup
+\ir helper_test_cleanup.sql
+\if :should_cleanup
+DROP DATABASE IF EXISTS cloudsync_test_41_src;
+DROP DATABASE IF EXISTS cloudsync_test_41_dst;
+\endif

test/postgresql/42_payload_idempotency.sql

@@ -0,0 +1,88 @@
+-- Test payload apply idempotency
+-- Applying the same payload multiple times must produce identical results.
+
+\set testid '42'
+\ir helper_test_init.sql
+
+\connect postgres
+\ir helper_psql_conn_setup.sql
+DROP DATABASE IF EXISTS cloudsync_test_42_src;
+DROP DATABASE IF EXISTS cloudsync_test_42_dst;
+CREATE DATABASE cloudsync_test_42_src;
+CREATE DATABASE cloudsync_test_42_dst;
+
+-- Setup source with data
+\connect cloudsync_test_42_src
+\ir helper_psql_conn_setup.sql
+CREATE EXTENSION IF NOT EXISTS cloudsync;
+CREATE TABLE test_tbl (id TEXT PRIMARY KEY, val TEXT, num INTEGER);
+SELECT cloudsync_init('test_tbl', 'CLS', true) AS _init_src \gset
+INSERT INTO test_tbl VALUES ('id1', 'hello', 10);
+INSERT INTO test_tbl VALUES ('id2', 'world', 20);
+UPDATE test_tbl SET val = 'hello_updated' WHERE id = 'id1';
+
+-- Encode payload
+SELECT encode(cloudsync_payload_encode(tbl, pk, col_name, col_value, col_version, db_version, site_id, cl, seq), 'hex') AS payload_hex
+FROM cloudsync_changes
+WHERE site_id = cloudsync_siteid() \gset
+
+-- Setup destination
+\connect cloudsync_test_42_dst
+\ir helper_psql_conn_setup.sql
+CREATE EXTENSION IF NOT EXISTS cloudsync;
+CREATE TABLE test_tbl (id TEXT PRIMARY KEY, val TEXT, num INTEGER);
+SELECT cloudsync_init('test_tbl', 'CLS', true) AS _init_dst \gset
+
+-- Apply #1
+SELECT cloudsync_payload_apply(decode(:'payload_hex', 'hex')) AS apply_1 \gset
+SELECT md5(COALESCE(string_agg(id || ':' || COALESCE(val, '') || ':' || COALESCE(num::text, ''), ',' ORDER BY id), '')) AS hash_1
+FROM test_tbl \gset
+SELECT COUNT(*) AS count_1 FROM test_tbl \gset
+
+-- Apply #2
+SELECT cloudsync_payload_apply(decode(:'payload_hex', 'hex')) AS apply_2 \gset
+SELECT md5(COALESCE(string_agg(id || ':' || COALESCE(val, '') || ':' || COALESCE(num::text, ''), ',' ORDER BY id), '')) AS hash_2
+FROM test_tbl \gset
+SELECT COUNT(*) AS count_2 FROM test_tbl \gset
+
+-- Apply #3
+SELECT cloudsync_payload_apply(decode(:'payload_hex', 'hex')) AS apply_3 \gset
+SELECT md5(COALESCE(string_agg(id || ':' || COALESCE(val, '') || ':' || COALESCE(num::text, ''), ',' ORDER BY id), '')) AS hash_3
+FROM test_tbl \gset
+SELECT COUNT(*) AS count_3 FROM test_tbl \gset
+
+-- Verify row count stays constant
+SELECT (:count_1::int = :count_2::int AND :count_2::int = :count_3::int) AS count_stable \gset
+\if :count_stable
+\echo [PASS] (:testid) Row count stable across 3 applies (:count_1 rows)
+\else
+\echo [FAIL] (:testid) Row count changed: :count_1 -> :count_2 -> :count_3
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Verify data hash is identical after each apply
+SELECT (:'hash_1' = :'hash_2' AND :'hash_2' = :'hash_3') AS hash_stable \gset
+\if :hash_stable
+\echo [PASS] (:testid) Data hash identical across 3 applies
+\else
+\echo [FAIL] (:testid) Data hash changed: :hash_1 -> :hash_2 -> :hash_3
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Verify data values are correct
+SELECT COUNT(*) = 1 AS data_ok
+FROM test_tbl
+WHERE id = 'id1' AND val = 'hello_updated' AND num = 10 \gset
+\if :data_ok
+\echo [PASS] (:testid) Data values correct after idempotent applies
+\else
+\echo [FAIL] (:testid) Data values incorrect
+SELECT (:fail::int + 1) AS fail \gset
+\endif
+
+-- Cleanup
+\ir helper_test_cleanup.sql
+\if :should_cleanup
+DROP DATABASE IF EXISTS cloudsync_test_42_src;
+DROP DATABASE IF EXISTS cloudsync_test_42_dst;
+\endif