Label printing unit test (#3047)

* Adds a very simple sample plugin for label printing

* Test mixin install status and API query

* Better error reporting for label printing API

* pep fixes

* fix assertation

* remove broken assertation

* igonre for coverage

* test the base process of printing

* refactor tests

* clean up basic test

* refactor url

* fix url creation

* test printing multiples

* test all printing endpoints

* test all list options - move api tests

* test for invalid filters

* refactor

* test with no part

* these should not happen
checks are in place upstream

* fix assertation

* do not cover continue parts

* test for wrong implementation

* ignore DB not ready

* remove covage from default parts

* fix url generation

* test debug mode

* fix url assertation

* check that nothing was rendered

Co-authored-by: Oliver Walters <oliver.henry.walters@gmail.com>

InvenTree/plugin/base/label/label.py

@@ -26,13 +26,13 @@ def print_label(plugin_slug, label_image, label_instance=None, user=None):
 
     plugin = registry.plugins.get(plugin_slug, None)
 
-    if plugin is None:
+    if plugin is None:  # pragma: no cover
         logger.error(f"Could not find matching plugin for '{plugin_slug}'")
         return
 
     try:
         plugin.print_label(label_image, width=label_instance.width, height=label_instance.height)
-    except Exception as e:
+    except Exception as e:  # pragma: no cover
         # Plugin threw an error - notify the user who attempted to print
 
         ctx = {

InvenTree/plugin/base/label/test_label_mixin.py

@@ -0,0 +1,209 @@
+"""Unit tests for the label printing mixin"""
+
+from django.apps import apps
+from django.urls import reverse
+
+from common.models import InvenTreeSetting
+from InvenTree.api_tester import InvenTreeAPITestCase
+from label.models import PartLabel, StockItemLabel, StockLocationLabel
+from part.models import Part
+from plugin.base.label.mixins import LabelPrintingMixin
+from plugin.helpers import MixinNotImplementedError
+from plugin.plugin import InvenTreePlugin
+from plugin.registry import registry
+from stock.models import StockItem, StockLocation
+
+
+class LabelMixinTests(InvenTreeAPITestCase):
+    """Test that the Label mixin operates correctly"""
+
+    fixtures = [
+        'category',
+        'part',
+        'location',
+        'stock',
+    ]
+
+    roles = 'all'
+
+    def do_activate_plugin(self):
+        """Activate the 'samplelabel' plugin"""
+
+        config = registry.get_plugin('samplelabel').plugin_config()
+        config.active = True
+        config.save()
+
+    def do_url(self, parts, plugin_ref, label, url_name: str = 'api-part-label-print', url_single: str = 'part', invalid: bool = False):
+        """Generate an URL to print a label"""
+        # Construct URL
+        kwargs = {}
+        if label:
+            kwargs["pk"] = label.pk
+
+        url = reverse(url_name, kwargs=kwargs)
+
+        # Append part filters
+        if not parts:
+            pass
+        elif len(parts) == 1:
+            url += f'?{url_single}={parts[0].pk}'
+        elif len(parts) > 1:
+            url += '?' + '&'.join([f'{url_single}s={item.pk}' for item in parts])
+
+        # Append an invalid item
+        if invalid:
+            url += f'&{url_single}{"s" if len(parts) > 1 else ""}=abc'
+
+        # Append plugin reference
+        if plugin_ref:
+            url += f'&plugin={plugin_ref}'
+
+        return url
+
+    def test_wrong_implementation(self):
+        """Test that a wrong implementation raises an error"""
+
+        class WrongPlugin(LabelPrintingMixin, InvenTreePlugin):
+            pass
+
+        with self.assertRaises(MixinNotImplementedError):
+            plugin = WrongPlugin()
+            plugin.print_label('test')
+
+    def test_installed(self):
+        """Test that the sample printing plugin is installed"""
+
+        # Get all label plugins
+        plugins = registry.with_mixin('labels')
+        self.assertEqual(len(plugins), 1)
+
+        # But, it is not 'active'
+        plugins = registry.with_mixin('labels', active=True)
+        self.assertEqual(len(plugins), 0)
+
+    def test_api(self):
+        """Test that we can filter the API endpoint by mixin"""
+
+        url = reverse('api-plugin-list')
+
+        # Try POST (disallowed)
+        response = self.client.post(url, {})
+        self.assertEqual(response.status_code, 405)
+
+        response = self.client.get(
+            url,
+            {
+                'mixin': 'labels',
+                'active': True,
+            }
+        )
+
+        # No results matching this query!
+        self.assertEqual(len(response.data), 0)
+
+        # What about inactive?
+        response = self.client.get(
+            url,
+            {
+                'mixin': 'labels',
+                'active': False,
+            }
+        )
+
+        self.assertEqual(len(response.data), 0)
+
+        self.do_activate_plugin()
+        # Should be available via the API now
+        response = self.client.get(
+            url,
+            {
+                'mixin': 'labels',
+                'active': True,
+            }
+        )
+
+        self.assertEqual(len(response.data), 1)
+        data = response.data[0]
+        self.assertEqual(data['key'], 'samplelabel')
+
+    def test_printing_process(self):
+        """Test that a label can be printed"""
+
+        # Ensure the labels were created
+        apps.get_app_config('label').create_labels()
+
+        # Lookup references
+        part = Part.objects.first()
+        plugin_ref = 'samplelabel'
+        label = PartLabel.objects.first()
+
+        url = self.do_url([part], plugin_ref, label)
+
+        # Non-exsisting plugin
+        response = self.get(f'{url}123', expected_code=404)
+        self.assertIn(f'Plugin \'{plugin_ref}123\' not found', str(response.content, 'utf8'))
+
+        # Inactive plugin
+        response = self.get(url, expected_code=400)
+        self.assertIn(f'Plugin \'{plugin_ref}\' is not enabled', str(response.content, 'utf8'))
+
+        # Active plugin
+        self.do_activate_plugin()
+
+        # Print one part
+        self.get(url, expected_code=200)
+
+        # Print multiple parts
+        self.get(self.do_url(Part.objects.all()[:2], plugin_ref, label), expected_code=200)
+
+        # Print multiple parts without a plugin
+        self.get(self.do_url(Part.objects.all()[:2], None, label), expected_code=200)
+
+        # Print multiple parts without a plugin in debug mode
+        InvenTreeSetting.set_setting('REPORT_DEBUG_MODE', True, None)
+        response = self.get(self.do_url(Part.objects.all()[:2], None, label), expected_code=200)
+        self.assertIn('@page', str(response.content))
+
+        # Print no part
+        self.get(self.do_url(None, plugin_ref, label), expected_code=400)
+
+    def test_printing_endpoints(self):
+        """Cover the endpoints not covered by `test_printing_process`"""
+        plugin_ref = 'samplelabel'
+
+        # Activate the label components
+        apps.get_app_config('label').create_labels()
+        self.do_activate_plugin()
+
+        def run_print_test(label, qs, url_name, url_single):
+            """Run tests on single and multiple page printing
+
+            Args:
+                label (_type_): class of the label
+                qs (_type_): class of the base queryset
+                url_name (_type_): url for endpoints
+                url_single (_type_): item lookup reference
+            """
+            label = label.objects.first()
+            qs = qs.objects.all()
+
+            # List endpoint
+            self.get(self.do_url(None, None, None, f'{url_name}-list', url_single), expected_code=200)
+
+            # List endpoint with filter
+            self.get(self.do_url(qs[:2], None, None, f'{url_name}-list', url_single, invalid=True), expected_code=200)
+
+            # Single page printing
+            self.get(self.do_url(qs[:1], plugin_ref, label, f'{url_name}-print', url_single), expected_code=200)
+
+            # Multi page printing
+            self.get(self.do_url(qs[:2], plugin_ref, label, f'{url_name}-print', url_single), expected_code=200)
+
+        # Test StockItemLabels
+        run_print_test(StockItemLabel, StockItem, 'api-stockitem-label', 'item')
+
+        # Test StockLocationLabels
+        run_print_test(StockLocationLabel, StockLocation, 'api-stocklocation-label', 'location')
+
+        # Test PartLabels
+        run_print_test(PartLabel, Part, 'api-part-label', 'part')

InvenTree/plugin/samples/integration/custom_panel_sample.py

@@ -120,7 +120,7 @@ class CustomPanelSample(PanelMixin, SettingsMixin, InvenTreePlugin):
                         'icon': 'fa-user',
                         'content_template': 'panel_demo/childless.html',  # Note that the panel content is rendered using a template file!
                     })
-            except:
+            except:  # pragma: no cover
                 pass
 
         return panels

InvenTree/plugin/samples/integration/label_sample.py

@@ -0,0 +1,18 @@
+
+from plugin import InvenTreePlugin
+from plugin.mixins import LabelPrintingMixin
+
+
+class SampleLabelPrinter(LabelPrintingMixin, InvenTreePlugin):
+    """
+    Sample plugin which provides a 'fake' label printer endpoint
+    """
+
+    NAME = "Label Printer"
+    SLUG = "samplelabel"
+    TITLE = "Sample Label Printer"
+    DESCRIPTION = "A sample plugin which provides a (fake) label printer interface"
+    VERSION = "0.1"
+
+    def print_label(self, label, **kwargs):
+        print("OK PRINTING")