🧪 Add tests for ModificationTracker serialization

tests/unit/tracker_serialization.test.ts

@@ -0,0 +1,107 @@
+
+import { describe, it } from 'node:test';
+import assert from 'node:assert';
+import { ModificationTracker } from '../../src/core/undo-history';
+import { LabeledModification } from '../../src/core/types';
+
+describe('ModificationTracker Serialization', () => {
+
+    it('should serialize and deserialize an empty tracker', () => {
+        const tracker = new ModificationTracker<LabeledModification>();
+        const serialized = tracker.serialize();
+
+        assert.ok(serialized instanceof Uint8Array);
+        assert.ok(serialized.length > 0);
+
+        const restored = ModificationTracker.deserialize<LabeledModification>(serialized);
+
+        assert.strictEqual(restored.entryCount, 0);
+        assert.strictEqual(restored.canStepBack, false);
+        assert.strictEqual(restored.canStepForward, false);
+    });
+
+    it('should serialize and deserialize a tracker with simple modifications', () => {
+        const tracker = new ModificationTracker<LabeledModification>();
+        const mod: LabeledModification = {
+            label: 'Test Mod',
+            description: 'Insert row',
+            modificationType: 'row_insert',
+            targetTable: 'users',
+            newValue: 'Alice'
+        };
+
+        tracker.record(mod);
+
+        const serialized = tracker.serialize();
+        const restored = ModificationTracker.deserialize<LabeledModification>(serialized);
+
+        assert.strictEqual(restored.entryCount, 1);
+
+        const lastMod = restored.stepBack();
+        assert.ok(lastMod);
+        assert.strictEqual(lastMod?.label, 'Test Mod');
+        assert.strictEqual(lastMod?.newValue, 'Alice');
+    });
+
+    it('should properly serialize and deserialize Uint8Array data', () => {
+        const tracker = new ModificationTracker<LabeledModification>();
+
+        // Create a Uint8Array with some data
+        const binaryData = new Uint8Array([1, 2, 3, 255, 0]);
+
+        const mod: LabeledModification = {
+            label: 'Binary Mod',
+            description: 'Update blob',
+            modificationType: 'cell_update',
+            targetTable: 'files',
+            priorValue: binaryData,
+            newValue: new Uint8Array([10, 20, 30])
+        };
+
+        tracker.record(mod);
+
+        const serialized = tracker.serialize();
+        const restored = ModificationTracker.deserialize<LabeledModification>(serialized);
+
+        assert.strictEqual(restored.entryCount, 1);
+
+        const lastMod = restored.stepBack();
+        assert.ok(lastMod);
+
+        // Verify priorValue
+        const restoredBinary = lastMod?.priorValue;
+        assert.ok(restoredBinary instanceof Uint8Array, 'priorValue should be Uint8Array');
+        assert.deepStrictEqual(restoredBinary, binaryData);
+
+        // Verify newValue
+        const restoredNewValue = lastMod?.newValue;
+        assert.ok(restoredNewValue instanceof Uint8Array, 'newValue should be Uint8Array');
+        assert.deepStrictEqual(restoredNewValue, new Uint8Array([10, 20, 30]));
+    });
+
+    it('should preserve checkpoint index', async () => {
+        const tracker = new ModificationTracker<LabeledModification>();
+        tracker.record({
+            label: '1', description: '1', modificationType: 'row_insert'
+        });
+
+        await tracker.createCheckpoint();
+
+        tracker.record({
+            label: '2', description: '2', modificationType: 'row_insert'
+        });
+
+        assert.strictEqual(tracker.hasUncommittedChanges(), true);
+
+        const serialized = tracker.serialize();
+        const restored = ModificationTracker.deserialize<LabeledModification>(serialized);
+
+        // Checkpoint index should be preserved (at 1)
+        // Total entries 2
+        assert.strictEqual(restored.entryCount, 2);
+
+        const uncommitted = restored.getUncommittedEntries();
+        assert.strictEqual(uncommitted.length, 1);
+        assert.strictEqual(uncommitted[0].label, '2');
+    });
+});