test(ctx): Add integration test for Preview button with real FileItems

tests/test_context_preview_button.py

@@ -46,6 +46,49 @@ def test_preview_button_empty_state_message():
   render_context_batch_actions(app, 0, 0)
   assert app.context_preview_text == '' or 'No files' in str(app.context_preview_text)
 
+
+def test_preview_generates_nonempty_for_real_files(monkeypatch):
+ """Integration test: Preview button should generate content when context_files has real FileItems."""
+ import src.project_manager as pm
+ import src.aggregate as agg
+ from src.models import FileItem
+
+ app = Mock(spec=App)
+ test_file = FileItem(path='tests/test_context_composition_decoupled.py', view_mode='summary')
+ app.context_files = [test_file]
+ app.files = []
+ app.controller = Mock()
+ app.controller.context_files = []
+ app.show_windows = {'Context Preview': False}
+ app.ui_selected_context_files = set()
+
+ def mock_flat_config(*args, **kwargs):
+  return {'files': {}, 'project': {}, 'output': {'output_dir': 'tests/artifacts'}, 'discussion': {'history': []}}
+
+ def mock_aggregate_run(flat, **kwargs):
+  paths = flat['files']['paths']
+  assert len(paths) == 1
+  assert paths[0].path == 'tests/test_context_composition_decoupled.py'
+  return ('Generated Markdown Content', Path('tests/artifacts/output.md'), [])
+
+ app.controller._do_generate.return_value = ('Generated Markdown Content', Path('tests/artifacts/output.md'), [], '', '')
+ monkeypatch.setattr(pm, 'flat_config', mock_flat_config)
+ monkeypatch.setattr(pm, 'save_project', lambda *args: None)
+ monkeypatch.setattr(agg, 'run', mock_aggregate_run)
+ monkeypatch.setattr(agg, 'build_markdown_no_history', lambda *args, **kwargs: 'stable')
+ monkeypatch.setattr(agg, 'build_discussion_text', lambda *args, **kwargs: 'disc')
+
+ from src.gui_2 import render_context_batch_actions
+ import unittest.mock as mock
+ with mock.patch('src.gui_2.imgui') as mock_imgui:
+  mock_imgui.button.return_value = True
+  mock_imgui.same_line = mock.Mock()
+  mock_imgui.text = mock.Mock()
+  mock_imgui.open_popup = mock.Mock()
+  render_context_batch_actions(app, 100, 50)
+  assert app.context_preview_text == 'Generated Markdown Content'
+  assert app.controller.context_files == app.context_files
+
 def test_text_viewer_window_invoked_in_render_loop():
  import src.gui_2 as gui_2
  assert hasattr(gui_2, 'render_text_viewer_window'), "render_text_viewer_window function must exist"