test: Field filter validation and Custom field as field filter

- Test to block Item fields (which aren’t in Website Item) in E Commerce Settings as filters
- Removed unnecessary function and setup in E Commerce Settings test
- Removed commented useless test
- Test to check custom field as filter

erpnext/e_commerce/doctype/e_commerce_settings/test_e_commerce_settings.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2021, Frappe Technologies Pvt. Ltd. and Contributors
+# Copyright (c) 2022, Frappe Technologies Pvt. Ltd. and Contributors
 # See license.txt
 
 import unittest
@@ -11,42 +11,32 @@ from erpnext.e_commerce.doctype.e_commerce_settings.e_commerce_settings import (
 
 
 class TestECommerceSettings(unittest.TestCase):
-	def setUp(self):
-		frappe.db.sql("""delete from `tabSingles` where doctype="Shipping Cart Settings" """)
-
-	def get_cart_settings(self):
-		return frappe.get_doc({"doctype": "E Commerce Settings", "company": "_Test Company"})
-
-	# NOTE: Exchangrate API has all enabled currencies that ERPNext supports.
-	# We aren't checking just currency exchange record anymore
-	# while validating price list currency exchange rate to that of company.
-	# The API is being used to fetch the rate which again almost always
-	# gives back a valid value (for valid currencies).
-	# This makes the test obsolete.
-	# Commenting because im not sure if there's a better test we can write
-
-	# def test_exchange_rate_exists(self):
-	# 	frappe.db.sql("""delete from `tabCurrency Exchange`""")
-
-	# 	cart_settings = self.get_cart_settings()
-	# 	cart_settings.price_list = "_Test Price List Rest of the World"
-	# 	self.assertRaises(ShoppingCartSetupError, cart_settings.validate_price_list_exchange_rate)
-
-	# 	from erpnext.setup.doctype.currency_exchange.test_currency_exchange import test_records as \
-	# 		currency_exchange_records
-	# 	frappe.get_doc(currency_exchange_records[0]).insert()
-	# 	cart_settings.validate_price_list_exchange_rate()
+	def tearDown(self):
+		frappe.db.rollback()
 
 	def test_tax_rule_validation(self):
 		frappe.db.sql("update `tabTax Rule` set use_for_shopping_cart = 0")
 
-		cart_settings = self.get_cart_settings()
+		cart_settings = frappe.get_doc("E Commerce Settings")
 		cart_settings.enabled = 1
 		if not frappe.db.get_value("Tax Rule", {"use_for_shopping_cart": 1}, "name"):
 			self.assertRaises(ShoppingCartSetupError, cart_settings.validate_tax_rule)
 
 		frappe.db.sql("update `tabTax Rule` set use_for_shopping_cart = 1")
 
+	def test_invalid_filter_fields(self):
+		"Check if Item fields are blocked in E Commerce Settings filter fields."
+		from frappe.custom.doctype.custom_field.custom_field import create_custom_field
+
+		create_custom_field(
+			"Item",
+			dict(owner="Administrator", fieldname="test_data", label="Test", fieldtype="Data"),
+		)
+		settings = frappe.get_doc("E Commerce Settings")
+		settings.append("filter_fields", {"fieldname": "test_data"})
+
+		self.assertRaises(frappe.ValidationError, settings.save)
+
 
 def setup_e_commerce_settings(values_dict):
 	"Accepts a dict of values that updates E Commerce Settings."

erpnext/e_commerce/product_data_engine/test_product_data_engine.py

@@ -277,6 +277,54 @@ class TestProductDataEngine(unittest.TestCase):
 		# tear down
 		setup_e_commerce_settings({"enable_attribute_filters": 1, "hide_variants": 0})
 
+	def test_custom_field_as_filter(self):
+		"Test if custom field functions as filter correctly."
+		from frappe.custom.doctype.custom_field.custom_field import create_custom_field
+
+		create_custom_field(
+			"Website Item",
+			dict(
+				owner="Administrator",
+				fieldname="supplier",
+				label="Supplier",
+				fieldtype="Link",
+				options="Supplier",
+				insert_after="on_backorder",
+			),
+		)
+
+		frappe.db.set_value(
+			"Website Item", {"item_code": "Test 11I Laptop"}, "supplier", "_Test Supplier"
+		)
+		frappe.db.set_value(
+			"Website Item", {"item_code": "Test 12I Laptop"}, "supplier", "_Test Supplier 1"
+		)
+
+		settings = frappe.get_doc("E Commerce Settings")
+		settings.append("filter_fields", {"fieldname": "supplier"})
+		settings.save()
+
+		filter_engine = ProductFiltersBuilder()
+		field_filters = filter_engine.get_field_filters()
+		custom_filter = field_filters[1]
+		filter_values = custom_filter[1]
+
+		self.assertEqual(custom_filter[0].options, "Supplier")
+		self.assertEqual(len(filter_values), 2)
+		self.assertIn("_Test Supplier", filter_values)
+
+		# test if custom filter works in query
+		field_filters = {"supplier": "_Test Supplier 1"}
+		engine = ProductQuery()
+		result = engine.query(
+			attributes={}, fields=field_filters, search_term=None, start=0, item_group=None
+		)
+		items = result.get("items")
+
+		# check if only 'Raw Material' are fetched in the right order
+		self.assertEqual(len(items), 1)
+		self.assertEqual(items[0].get("item_code"), "Test 12I Laptop")
+
 
 def create_variant_web_item():
 	"Create Variant and Template Website Items."