Snapshot URL datasets locally on add; preview tabular data as a table

src/app/stores/DatasetStore.test.ts

@@ -42,15 +42,82 @@ describe('save — create', () => {
     expect(ds?.rowCount).toBe(2);
   });
 
-  test('a valid URL infers format from the extension', () => {
+  test('save() does not commit a URL create — it must go through commitUrlSnapshot', () => {
+    store().startCreate();
+    store().updateForm({ name: 'Remote', source: 'url', input: 'https://example.com/data.csv' });
+    // The component fetches first; save() never touches the network, so a URL create
+    // through save() is a no-op rather than an unfetched record.
+    expect(store().save(T)).toBe(false);
+    expect(store().datasets).toHaveLength(0);
+  });
+});
+
+describe('commitUrlSnapshot — create from a fetched body', () => {
+  test('snapshots the body, infers format from content, and profiles it', () => {
     store().startCreate();
     store().updateForm({ name: 'Remote', source: 'url', input: 'https://example.com/data.csv' });
 
-    expect(store().save(T)).toBe(true);
+    expect(store().commitUrlSnapshot({ text: 'a,b\n1,2\n3,4' }, T)).toBe(true);
     const ds = selectSelectedDataset(store());
     expect(ds?.source).toBe('url');
+    expect(ds?.url).toBe('https://example.com/data.csv');
     expect(ds?.format).toBe('csv');
-    expect(ds?.rowCount).toBeNull(); // URL datasets aren't profiled
+    expect(ds?.data).toBe('a,b\n1,2\n3,4');
+    expect(ds?.rowCount).toBe(2);
+    expect(ds?.columns).toEqual(['a', 'b']);
+    expect(ds?.fetchedAt).toBe(T.toISOString());
+    expect(store().view).toBe('detail');
+  });
+
+  test('a duplicate name is rejected even with a successful fetch', () => {
+    store().add(
+      createDataset({ name: 'Dupe', data: [{ a: 1 }], format: 'json', source: 'inline', now: T }),
+    );
+    store().startCreate();
+    store().updateForm({ name: 'dupe', source: 'url', input: 'https://x/y.csv' });
+    expect(store().commitUrlSnapshot({ text: 'a\n1' }, T)).toBe(false);
+    expect(store().formError).toMatch(/already exists/i);
+  });
+});
+
+describe('URL dataset edits & refresh', () => {
+  const seedUrl = () => {
+    store().startCreate();
+    store().updateForm({ name: 'Remote', source: 'url', input: 'https://x/y.csv' });
+    store().commitUrlSnapshot({ text: 'a,b\n1,2' }, T);
+    return store().selectedId!;
+  };
+
+  test('a metadata-only edit (same URL) updates name without re-fetching', () => {
+    const id = seedUrl();
+    store().startEdit();
+    store().updateForm({ name: 'Renamed' }); // URL field stays https://x/y.csv
+    const later = new Date('2026-07-01T00:00:00Z');
+    expect(store().save(later)).toBe(true);
+    const ds = store().datasets.find((d) => d.id === id)!;
+    expect(ds.name).toBe('Renamed');
+    expect(ds.data).toBe('a,b\n1,2'); // snapshot untouched
+    expect(ds.fetchedAt).toBe(T.toISOString()); // not re-fetched
+    expect(ds.modified).toBe(later.toISOString());
+  });
+
+  test('refreshDataset re-snapshots, re-profiles, and advances fetchedAt', () => {
+    const id = seedUrl();
+    const later = new Date('2026-07-01T00:00:00Z');
+    expect(store().refreshDataset(id, { text: 'a,b\n1,2\n3,4\n5,6' }, later)).toBe(true);
+    const ds = store().datasets.find((d) => d.id === id)!;
+    expect(ds.rowCount).toBe(3);
+    expect(ds.fetchedAt).toBe(later.toISOString());
+    expect(ds.modified).toBe(later.toISOString());
+    expect(ds.name).toBe('Remote'); // preserved
+  });
+
+  test('refreshDataset is a no-op for an inline dataset', () => {
+    store().add(
+      createDataset({ name: 'Inline', data: [{ a: 1 }], format: 'json', source: 'inline', now: T }),
+    );
+    const id = store().selectedId!;
+    expect(store().refreshDataset(id, { text: 'a\n1' }, T)).toBe(false);
   });
 });