Consolidate AWB preview handling

home/node_preview.py

@@ -0,0 +1,31 @@
+"""Helpers for optional node previews."""
+
+from __future__ import annotations
+
+from aiida import orm
+
+AWB_UNAVAILABLE_MESSAGE = (
+    "The AiiDAlab widgets are not available. Please install it with "
+    "`pip install aiidalab-widgets-base` to use this feature."
+)
+
+
+def _load_awb_viewer():
+    from aiidalab_widgets_base import viewer  # noqa: PLC0415
+
+    return viewer
+
+
+def render_unavailable_preview() -> str:
+    """Return the fallback message shown when AWB is unavailable."""
+    return AWB_UNAVAILABLE_MESSAGE
+
+
+def render_node_preview(node: orm.Node) -> object:
+    """Render a node preview using AWB when it is available."""
+    try:
+        viewer = _load_awb_viewer()
+    except ImportError:
+        return render_unavailable_preview()
+
+    return viewer(node)

home/process.py

@@ -28,6 +28,8 @@
 from aiida.tools.query.calculation import CalculationQueryBuilder
 from IPython.display import HTML, Javascript, clear_output, display
 
+from home.node_preview import render_node_preview
+
 
 class CantRegisterCallbackError(Exception):
     """Exception raised when trying to register a callback after monitoring has started."""
@@ -304,22 +306,13 @@ def flatten(d, parent_key="", sep="."):
 
     def show_selected_input(self, change=None):
         """Function that displays process inputs selected in the `inputs` Dropdown widget."""
-        try:
-            from aiidalab_widgets_base import viewer  # noqa PLC0415
-
-            with self.output:
-                self.info.value = ""
-                clear_output()
-                if change["new"]:
-                    selected_input = orm.load_node(change["new"])
-                    self.info.value = f"PK: {selected_input.pk}"
-                    display(viewer(selected_input))
-        except ImportError:
-            self.output.clear_output()
-            with self.output:
-                print(
-                    "The AiiDAlab widgets are not available. Please install it with `pip install aiidalab-widgets-base` to use this feature."
-                )
+        with self.output:
+            self.info.value = ""
+            clear_output()
+            if change["new"]:
+                selected_input = orm.load_node(change["new"])
+                self.info.value = f"PK: {selected_input.pk}"
+                display(render_node_preview(selected_input))
 
 
 class ProcessMonitor(tl.HasTraits):
@@ -435,22 +428,13 @@ def __init__(self, process=None, **kwargs):
 
     def show_selected_output(self, change=None):
         """Function that displays process output selected in the `outputs` Dropdown widget."""
-        try:
-            from aiidalab_widgets_base import viewer  # noqa PLC0415
-
-            with self.output:
-                self.info.value = ""
-                clear_output()
-                if change["new"]:
-                    selected_output = self.process.outputs[change["new"]]
-                    self.info.value = f"PK: {selected_output.pk}"
-                    display(viewer(selected_output))
-        except ImportError:
-            self.output.clear_output()
-            with self.output:
-                print(
-                    "The AiiDAlab widgets are not available. Please install it with `pip install aiidalab-widgets-base` to use this feature."
-                )
+        with self.output:
+            self.info.value = ""
+            clear_output()
+            if change["new"]:
+                selected_output = self.process.outputs[change["new"]]
+                self.info.value = f"PK: {selected_output.pk}"
+                display(render_node_preview(selected_output))
 
 
 class ProcessReportWidget(ipw.HTML):

tests/test_process.py

@@ -1,23 +1,46 @@
-import sys
-import types
+import inspect
 
 import pytest
 from aiida import orm
 
+from home import node_preview
 from home import process as home_process
 
 pytestmark = pytest.mark.usefixtures("aiida_profile_clean")
 
 
 @pytest.fixture
-def mock_viewer_module(monkeypatch):
-    """Provide a lightweight viewer module for optional AWB integration paths."""
-    module = types.ModuleType("aiidalab_widgets_base")
-    module.viewer = lambda _: "mock-viewer"
-    monkeypatch.setitem(sys.modules, "aiidalab_widgets_base", module)
+def capture_display(monkeypatch):
+    displayed = []
+    monkeypatch.setattr(home_process, "display", displayed.append)
+    return displayed
 
 
-def test_process_inputs_widget(generate_calc_job_node, mock_viewer_module):
+def test_render_node_preview_uses_awb_when_available(monkeypatch):
+    node = orm.Int(1)
+
+    monkeypatch.setattr(
+        node_preview, "_load_awb_viewer", lambda: lambda _: "mock-viewer"
+    )
+
+    assert node_preview.render_node_preview(node) == "mock-viewer"
+
+
+def test_render_node_preview_returns_message_when_awb_is_unavailable(monkeypatch):
+    def raise_import_error():
+        raise ImportError
+
+    monkeypatch.setattr(node_preview, "_load_awb_viewer", raise_import_error)
+
+    assert (
+        node_preview.render_node_preview(orm.Int(1))
+        == node_preview.render_unavailable_preview()
+    )
+
+
+def test_process_inputs_widget_uses_node_preview_adapter(
+    generate_calc_job_node, monkeypatch, capture_display
+):
     process = generate_calc_job_node(
         inputs={
             "parameters": orm.Int(1),
@@ -27,6 +50,8 @@ def test_process_inputs_widget(generate_calc_job_node, mock_viewer_module):
         }
     )
 
+    monkeypatch.setattr(home_process, "render_node_preview", lambda _: "mock-viewer")
+
     home_process.ProcessInputsWidget()
 
     widget = home_process.ProcessInputsWidget(process=process)
@@ -38,16 +63,30 @@ def test_process_inputs_widget(generate_calc_job_node, mock_viewer_module):
     widget._inputs.value = nested_uuid
     selected_input = orm.load_node(nested_uuid)
     assert widget.info.value == f"PK: {selected_input.pk}"
+    assert capture_display == ["mock-viewer"]
 
 
-def test_process_outputs_widget(multiply_add_completed_workchain, mock_viewer_module):
+def test_process_outputs_widget_shows_unavailable_message(
+    multiply_add_completed_workchain, monkeypatch, capture_display
+):
+    monkeypatch.setattr(
+        home_process,
+        "render_node_preview",
+        lambda _: node_preview.render_unavailable_preview(),
+    )
+
     home_process.ProcessOutputsWidget()
 
     widget = home_process.ProcessOutputsWidget(process=multiply_add_completed_workchain)
     widget.show_selected_output(change={"new": "result"})
 
     selected_output = multiply_add_completed_workchain.outputs["result"]
     assert widget.info.value == f"PK: {selected_output.pk}"
+    assert capture_display == [node_preview.render_unavailable_preview()]
+
+
+def test_process_module_does_not_import_awb_directly():
+    assert "aiidalab_widgets_base" not in inspect.getsource(home_process)
 
 
 def test_process_report_widget(multiply_add_completed_workchain):