feat(export): batch wafer-map PNG export from file list

- BatchExport worker + BatchExportController (threaded, busy flag)
- SourcePanel: Export Maps button → FolderDialog → batch export
  with progress/summary banner (dismissible)
- StreamControlPanel: name single export after loaded CSV + timestamp

tests/test_batch_export.py

@@ -0,0 +1,93 @@
+"""Tests for src/pygui/backend/wafer/batch_export.py."""
+import pytest
+
+pytestmark = pytest.mark.usefixtures("qapp")
+
+
+def _write_single_frame_csv(path, wafer_id="F12"):
+    lines = [
+        f"Wafer ID={wafer_id}",
+        "Acquisition Date=03/26/2025",
+        "Label,1,2,3",
+        "X (mm),0,10,20",
+        "Y (mm),0,10,20",
+        "data",
+        "0.0,149.0,150.0,151.0",
+    ]
+    path.write_text("\n".join(lines) + "\n", encoding="utf-8")
+
+
+def test_export_batch_writes_png_for_valid_file(tmp_path):
+    from pygui.backend.wafer.batch_export import export_batch
+
+    csv_path = tmp_path / "f_run.csv"
+    _write_single_frame_csv(csv_path)
+    out_dir = tmp_path / "out"
+    out_dir.mkdir()
+
+    results = export_batch([str(csv_path)], str(out_dir), timestamp="20260101_000000")
+
+    assert len(results) == 1
+    assert results[0].success is True
+    expected_png = out_dir / "f_run_20260101_000000.png"
+    assert expected_png.exists()
+    assert results[0].output_path == str(expected_png)
+
+
+def test_export_batch_skips_bad_file_and_continues(tmp_path):
+    from pygui.backend.wafer.batch_export import export_batch
+
+    bad_csv = tmp_path / "corrupt.csv"
+    bad_csv.write_text("not a valid wafer csv\n", encoding="utf-8")
+
+    good_csv = tmp_path / "f_run.csv"
+    _write_single_frame_csv(good_csv)
+
+    out_dir = tmp_path / "out"
+    out_dir.mkdir()
+
+    results = export_batch(
+        [str(bad_csv), str(good_csv)], str(out_dir), timestamp="20260101_000000"
+    )
+
+    assert len(results) == 2
+    assert results[0].success is False
+    assert results[0].error != ""
+    assert not (out_dir / "corrupt_20260101_000000.png").exists()
+
+    assert results[1].success is True
+    assert (out_dir / "f_run_20260101_000000.png").exists()
+
+
+def _write_two_frame_csv(path, wafer_id="F12"):
+    lines = [
+        f"Wafer ID={wafer_id}",
+        "Acquisition Date=03/26/2025",
+        "Label,1,2,3",
+        "X (mm),0,10,20",
+        "Y (mm),0,10,20",
+        "data",
+        "0.0,100.0,101.0,102.0",
+        "1.0,149.0,150.0,151.0",
+    ]
+    path.write_text("\n".join(lines) + "\n", encoding="utf-8")
+
+
+def test_export_batch_renders_last_frame_of_multiframe_file(tmp_path):
+    from pygui.backend.wafer.batch_export import export_batch
+
+    multi_csv = tmp_path / "multi.csv"
+    _write_two_frame_csv(multi_csv)
+
+    single_csv = tmp_path / "single.csv"
+    _write_single_frame_csv(single_csv)  # same values as multi's 2nd (last) row
+
+    out_dir = tmp_path / "out"
+    out_dir.mkdir()
+
+    export_batch([str(multi_csv)], str(out_dir), timestamp="20260101_000000")
+    export_batch([str(single_csv)], str(out_dir), timestamp="20260101_000000")
+
+    multi_png = (out_dir / "multi_20260101_000000.png").read_bytes()
+    single_png = (out_dir / "single_20260101_000000.png").read_bytes()
+    assert multi_png == single_png

tests/test_batch_export_controller.py

@@ -0,0 +1,59 @@
+"""Tests for src/pygui/backend/controllers/batch_export_controller.py."""
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+from pygui.backend.controllers.batch_export_controller import BatchExportController
+from pygui.backend.wafer.batch_export import BatchExportResult
+
+pytestmark = pytest.mark.usefixtures("qapp")
+
+
+@pytest.fixture
+def controller():
+    return BatchExportController()
+
+
+def test_start_spawns_thread_and_sets_busy(controller):
+    with patch("threading.Thread") as mock_thread:
+        controller.start(["a.csv", "b.csv"], "/tmp/out")
+        mock_thread.assert_called_once()
+        assert controller.busy is True
+
+
+def test_start_ignores_call_while_already_busy(controller):
+    with patch("threading.Thread") as mock_thread:
+        controller.start(["a.csv"], "/tmp/out")
+        controller.start(["b.csv"], "/tmp/out")
+        mock_thread.assert_called_once()
+
+
+def test_handle_batch_finished_reports_all_succeeded(controller):
+    finished = MagicMock()
+    controller.exportFinished.connect(finished)
+    controller._busy = True
+
+    results = [
+        BatchExportResult("a.csv", "a.png", True),
+        BatchExportResult("b.csv", "b.png", True),
+        BatchExportResult("c.csv", "c.png", True),
+    ]
+    controller._handle_batch_finished(results)
+
+    finished.assert_called_once_with("Exported 3/3")
+    assert controller.busy is False
+
+
+def test_handle_batch_finished_reports_failures(controller):
+    finished = MagicMock()
+    controller.exportFinished.connect(finished)
+    controller._busy = True
+
+    results = [
+        BatchExportResult("a.csv", "a.png", True),
+        BatchExportResult("b.csv", "b.png", False, "parse error"),
+    ]
+    controller._handle_batch_finished(results)
+
+    finished.assert_called_once_with("Exported 1/2 — 1 failed")
+    assert controller.busy is False