test: basic tests for controllers/queries (#27422)

diff --git a/erpnext/controllers/queries.py b/erpnext/controllers/queries.py
index aafaf5b..ccd417b 100644
--- a/erpnext/controllers/queries.py
+++ b/erpnext/controllers/queries.py
@@ -307,7 +307,7 @@
 @frappe.validate_and_sanitize_search_inputs
 def get_project_name(doctype, txt, searchfield, start, page_len, filters):
 	cond = ''
-	if filters.get('customer'):
+	if filters and filters.get('customer'):
 		cond = """(`tabProject`.customer = %s or
 			ifnull(`tabProject`.customer,"")="") and""" %(frappe.db.escape(filters.get("customer")))
 
diff --git a/erpnext/controllers/tests/test_queries.py b/erpnext/controllers/tests/test_queries.py
new file mode 100644
index 0000000..05541d1
--- /dev/null
+++ b/erpnext/controllers/tests/test_queries.py
@@ -0,0 +1,87 @@
+import unittest
+from functools import partial
+
+from erpnext.controllers import queries
+
+
+def add_default_params(func, doctype):
+	return partial(
+		func, doctype=doctype, txt="", searchfield="name", start=0, page_len=20, filters=None
+	)
+
+
+class TestQueries(unittest.TestCase):
+
+	# All tests are based on doctype/test_records.json
+
+	def assert_nested_in(self, item, container):
+		self.assertIn(item, [vals for tuples in container for vals in tuples])
+
+	def test_employee_query(self):
+		query = add_default_params(queries.employee_query, "Employee")
+
+		self.assertGreaterEqual(len(query(txt="_Test Employee")), 3)
+		self.assertGreaterEqual(len(query(txt="_Test Employee 1")), 1)
+
+	def test_lead_query(self):
+		query = add_default_params(queries.lead_query, "Lead")
+
+		self.assertGreaterEqual(len(query(txt="_Test Lead")), 4)
+		self.assertEqual(len(query(txt="_Test Lead 4")), 1)
+
+	def test_customer_query(self):
+		query = add_default_params(queries.customer_query, "Customer")
+
+		self.assertGreaterEqual(len(query(txt="_Test Customer")), 7)
+		self.assertGreaterEqual(len(query(txt="_Test Customer USD")), 1)
+
+	def test_supplier_query(self):
+		query = add_default_params(queries.supplier_query, "Supplier")
+
+		self.assertGreaterEqual(len(query(txt="_Test Supplier")), 7)
+		self.assertGreaterEqual(len(query(txt="_Test Supplier USD")), 1)
+
+	def test_item_query(self):
+		query = add_default_params(queries.item_query, "Item")
+
+		self.assertGreaterEqual(len(query(txt="_Test Item")), 7)
+		self.assertEqual(len(query(txt="_Test Item Home Desktop 100 3")), 1)
+
+		fg_item = "_Test FG Item"
+		stock_items = query(txt=fg_item, filters={"is_stock_item": 1})
+		self.assert_nested_in("_Test FG Item", stock_items)
+
+		bundled_stock_items = query(txt="_test product bundle item 5", filters={"is_stock_item": 1})
+		self.assertEqual(len(bundled_stock_items), 0)
+
+	def test_bom_qury(self):
+		query = add_default_params(queries.bom, "BOM")
+
+		self.assertGreaterEqual(len(query(txt="_Test Item Home Desktop Manufactured")), 1)
+
+	def test_project_query(self):
+		query = add_default_params(queries.get_project_name, "BOM")
+
+		self.assertGreaterEqual(len(query(txt="_Test Project")), 1)
+
+	def test_account_query(self):
+		query = add_default_params(queries.get_account_list, "Account")
+
+		debtor_accounts = query(txt="Debtors", filters={"company": "_Test Company"})
+		self.assert_nested_in("Debtors - _TC", debtor_accounts)
+
+	def test_income_account_query(self):
+		query = add_default_params(queries.get_income_account, "Account")
+
+		self.assertGreaterEqual(len(query(filters={"company": "_Test Company"})), 1)
+
+	def test_expense_account_query(self):
+		query = add_default_params(queries.get_expense_account, "Account")
+
+		self.assertGreaterEqual(len(query(filters={"company": "_Test Company"})), 1)
+
+	def test_warehouse_query(self):
+		query = add_default_params(queries.warehouse_query, "Account")
+
+		wh = query(filters=[["Bin", "item_code", "=", "_Test Item"]])
+		self.assertGreaterEqual(len(wh), 1)