refactor(test): make use of mixin in ar/ap report tests
diff --git a/erpnext/accounts/report/accounts_receivable/test_accounts_receivable.py b/erpnext/accounts/report/accounts_receivable/test_accounts_receivable.py
index 6f1889b..0099e79 100644
--- a/erpnext/accounts/report/accounts_receivable/test_accounts_receivable.py
+++ b/erpnext/accounts/report/accounts_receivable/test_accounts_receivable.py
@@ -8,20 +8,17 @@
 from erpnext.accounts.doctype.payment_entry.payment_entry import get_payment_entry
 from erpnext.accounts.doctype.sales_invoice.test_sales_invoice import create_sales_invoice
 from erpnext.accounts.report.accounts_receivable.accounts_receivable import execute
+from erpnext.accounts.test.accounts_mixin import AccountsTestMixin
 from erpnext.selling.doctype.sales_order.test_sales_order import make_sales_order
 
 
-class TestAccountsReceivable(FrappeTestCase):
+class TestAccountsReceivable(AccountsTestMixin, FrappeTestCase):
 	def setUp(self):
-		frappe.db.sql("delete from `tabSales Invoice` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabSales Order` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabPayment Entry` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabGL Entry` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabPayment Ledger Entry` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabJournal Entry` where company='_Test Company 2'")
-		frappe.db.sql("delete from `tabExchange Rate Revaluation` where company='_Test Company 2'")
-
-		self.create_usd_account()
+		self.create_company()
+		self.create_customer()
+		self.create_item()
+		self.create_usd_receivable_account()
+		self.clear_old_entries()
 
 	def tearDown(self):
 		frappe.db.rollback()
@@ -49,9 +46,61 @@
 			debtors_usd.account_type = debtors.account_type
 			self.debtors_usd = debtors_usd.save().name
 
+	def create_sales_invoice(self, no_payment_schedule=False, do_not_submit=False):
+		frappe.set_user("Administrator")
+		si = create_sales_invoice(
+			item=self.item,
+			company=self.company,
+			customer=self.customer,
+			debit_to=self.debit_to,
+			posting_date=today(),
+			parent_cost_center=self.cost_center,
+			cost_center=self.cost_center,
+			rate=100,
+			price_list_rate=100,
+			do_not_save=1,
+		)
+		if not no_payment_schedule:
+			si.append(
+				"payment_schedule",
+				dict(due_date=getdate(add_days(today(), 30)), invoice_portion=30.00, payment_amount=30),
+			)
+			si.append(
+				"payment_schedule",
+				dict(due_date=getdate(add_days(today(), 60)), invoice_portion=50.00, payment_amount=50),
+			)
+			si.append(
+				"payment_schedule",
+				dict(due_date=getdate(add_days(today(), 90)), invoice_portion=20.00, payment_amount=20),
+			)
+		si = si.save()
+		if not do_not_submit:
+			si = si.submit()
+		return si
+
+	def create_payment_entry(self, docname):
+		pe = get_payment_entry("Sales Invoice", docname, bank_account=self.cash, party_amount=40)
+		pe.paid_from = self.debit_to
+		pe.insert()
+		pe.submit()
+
+	def create_credit_note(self, docname):
+		credit_note = create_sales_invoice(
+			company=self.company,
+			customer=self.customer,
+			item=self.item,
+			qty=-1,
+			debit_to=self.debit_to,
+			cost_center=self.cost_center,
+			is_return=1,
+			return_against=docname,
+		)
+
+		return credit_note
+
 	def test_accounts_receivable(self):
 		filters = {
-			"company": "_Test Company 2",
+			"company": self.company,
 			"based_on_payment_terms": 1,
 			"report_date": today(),
 			"range1": 30,
@@ -61,7 +110,9 @@
 		}
 
 		# check invoice grand total and invoiced column's value for 3 payment terms
-		name = make_sales_invoice().name
+		si = self.create_sales_invoice()
+		name = si.name
+
 		report = execute(filters)
 
 		expected_data = [[100, 30], [100, 50], [100, 20]]
@@ -71,7 +122,7 @@
 			self.assertEqual(expected_data[i - 1], [row.invoice_grand_total, row.invoiced])
 
 		# check invoice grand total, invoiced, paid and outstanding column's value after payment
-		make_payment(name)
+		self.create_payment_entry(si.name)
 		report = execute(filters)
 
 		expected_data_after_payment = [[100, 50, 10, 40], [100, 20, 0, 20]]
@@ -84,10 +135,10 @@
 			)
 
 		# check invoice grand total, invoiced, paid and outstanding column's value after credit note
-		make_credit_note(name)
+		self.create_credit_note(si.name)
 		report = execute(filters)
 
-		expected_data_after_credit_note = [100, 0, 0, 40, -40, "Debtors - _TC2"]
+		expected_data_after_credit_note = [100, 0, 0, 40, -40, self.debit_to]
 
 		row = report[1][0]
 		self.assertEqual(
@@ -108,21 +159,20 @@
 		"""
 
 		so = make_sales_order(
-			company="_Test Company 2",
-			customer="_Test Customer 2",
-			warehouse="Finished Goods - _TC2",
-			currency="EUR",
-			debit_to="Debtors - _TC2",
-			income_account="Sales - _TC2",
-			expense_account="Cost of Goods Sold - _TC2",
-			cost_center="Main - _TC2",
+			company=self.company,
+			customer=self.customer,
+			warehouse=self.warehouse,
+			debit_to=self.debit_to,
+			income_account=self.income_account,
+			expense_account=self.expense_account,
+			cost_center=self.cost_center,
 		)
 
 		pe = get_payment_entry(so.doctype, so.name)
 		pe = pe.save().submit()
 
 		filters = {
-			"company": "_Test Company 2",
+			"company": self.company,
 			"based_on_payment_terms": 0,
 			"report_date": today(),
 			"range1": 30,
@@ -147,34 +197,32 @@
 		)
 
 	@change_settings(
-		"Accounts Settings", {"allow_multi_currency_invoices_against_single_party_account": 1}
+		"Accounts Settings",
+		{"allow_multi_currency_invoices_against_single_party_account": 1, "allow_stale": 0},
 	)
 	def test_exchange_revaluation_for_party(self):
 		"""
-		Exchange Revaluation for party on Receivable/Payable shoule be included
+		Exchange Revaluation for party on Receivable/Payable should be included
 		"""
 
-		company = "_Test Company 2"
-		customer = "_Test Customer 2"
-
 		# Using Exchange Gain/Loss account for unrealized as well.
-		company_doc = frappe.get_doc("Company", company)
+		company_doc = frappe.get_doc("Company", self.company)
 		company_doc.unrealized_exchange_gain_loss_account = company_doc.exchange_gain_loss_account
 		company_doc.save()
 
-		si = make_sales_invoice(no_payment_schedule=True, do_not_submit=True)
+		si = self.create_sales_invoice(no_payment_schedule=True, do_not_submit=True)
 		si.currency = "USD"
-		si.conversion_rate = 0.90
+		si.conversion_rate = 80
 		si.debit_to = self.debtors_usd
 		si = si.save().submit()
 
 		# Exchange Revaluation
 		err = frappe.new_doc("Exchange Rate Revaluation")
-		err.company = company
+		err.company = self.company
 		err.posting_date = today()
 		accounts = err.get_accounts_data()
 		err.extend("accounts", accounts)
-		err.accounts[0].new_exchange_rate = 0.95
+		err.accounts[0].new_exchange_rate = 85
 		row = err.accounts[0]
 		row.new_balance_in_base_currency = flt(
 			row.new_exchange_rate * flt(row.balance_in_account_currency)
@@ -189,7 +237,7 @@
 		je = je.submit()
 
 		filters = {
-			"company": company,
+			"company": self.company,
 			"report_date": today(),
 			"range1": 30,
 			"range2": 60,
@@ -198,7 +246,7 @@
 		}
 		report = execute(filters)
 
-		expected_data_for_err = [0, -5, 0, 5]
+		expected_data_for_err = [0, -500, 0, 500]
 		row = [x for x in report[1] if x.voucher_type == je.doctype and x.voucher_no == je.name][0]
 		self.assertEqual(
 			expected_data_for_err,
@@ -214,46 +262,43 @@
 		"""
 		Payment against credit/debit note should be considered against the parent invoice
 		"""
-		company = "_Test Company 2"
-		customer = "_Test Customer 2"
 
-		si1 = make_sales_invoice()
+		si1 = self.create_sales_invoice()
 
-		pe = get_payment_entry("Sales Invoice", si1.name, bank_account="Cash - _TC2")
-		pe.paid_from = "Debtors - _TC2"
+		pe = get_payment_entry(si1.doctype, si1.name, bank_account=self.cash)
+		pe.paid_from = self.debit_to
 		pe.insert()
 		pe.submit()
 
-		cr_note = make_credit_note(si1.name)
+		cr_note = self.create_credit_note(si1.name)
 
-		si2 = make_sales_invoice()
+		si2 = self.create_sales_invoice()
 
 		# manually link cr_note with si2 using journal entry
 		je = frappe.new_doc("Journal Entry")
-		je.company = company
+		je.company = self.company
 		je.voucher_type = "Credit Note"
 		je.posting_date = today()
 
-		debit_account = "Debtors - _TC2"
 		debit_entry = {
-			"account": debit_account,
+			"account": self.debit_to,
 			"party_type": "Customer",
-			"party": customer,
+			"party": self.customer,
 			"debit": 100,
 			"debit_in_account_currency": 100,
 			"reference_type": cr_note.doctype,
 			"reference_name": cr_note.name,
-			"cost_center": "Main - _TC2",
+			"cost_center": self.cost_center,
 		}
 		credit_entry = {
-			"account": debit_account,
+			"account": self.debit_to,
 			"party_type": "Customer",
-			"party": customer,
+			"party": self.customer,
 			"credit": 100,
 			"credit_in_account_currency": 100,
 			"reference_type": si2.doctype,
 			"reference_name": si2.name,
-			"cost_center": "Main - _TC2",
+			"cost_center": self.cost_center,
 		}
 
 		je.append("accounts", debit_entry)
@@ -261,7 +306,7 @@
 		je = je.save().submit()
 
 		filters = {
-			"company": company,
+			"company": self.company,
 			"report_date": today(),
 			"range1": 30,
 			"range2": 60,
@@ -270,65 +315,3 @@
 		}
 		report = execute(filters)
 		self.assertEqual(report[1], [])
-
-
-def make_sales_invoice(no_payment_schedule=False, do_not_submit=False):
-	frappe.set_user("Administrator")
-
-	si = create_sales_invoice(
-		company="_Test Company 2",
-		customer="_Test Customer 2",
-		currency="EUR",
-		warehouse="Finished Goods - _TC2",
-		debit_to="Debtors - _TC2",
-		income_account="Sales - _TC2",
-		expense_account="Cost of Goods Sold - _TC2",
-		cost_center="Main - _TC2",
-		do_not_save=1,
-	)
-
-	if not no_payment_schedule:
-		si.append(
-			"payment_schedule",
-			dict(due_date=getdate(add_days(today(), 30)), invoice_portion=30.00, payment_amount=30),
-		)
-		si.append(
-			"payment_schedule",
-			dict(due_date=getdate(add_days(today(), 60)), invoice_portion=50.00, payment_amount=50),
-		)
-		si.append(
-			"payment_schedule",
-			dict(due_date=getdate(add_days(today(), 90)), invoice_portion=20.00, payment_amount=20),
-		)
-
-	si = si.save()
-
-	if not do_not_submit:
-		si = si.submit()
-
-	return si
-
-
-def make_payment(docname):
-	pe = get_payment_entry("Sales Invoice", docname, bank_account="Cash - _TC2", party_amount=40)
-	pe.paid_from = "Debtors - _TC2"
-	pe.insert()
-	pe.submit()
-
-
-def make_credit_note(docname):
-	credit_note = create_sales_invoice(
-		company="_Test Company 2",
-		customer="_Test Customer 2",
-		currency="EUR",
-		qty=-1,
-		warehouse="Finished Goods - _TC2",
-		debit_to="Debtors - _TC2",
-		income_account="Sales - _TC2",
-		expense_account="Cost of Goods Sold - _TC2",
-		cost_center="Main - _TC2",
-		is_return=1,
-		return_against=docname,
-	)
-
-	return credit_note
diff --git a/erpnext/accounts/test/accounts_mixin.py b/erpnext/accounts/test/accounts_mixin.py
index debfffd..bf01362 100644
--- a/erpnext/accounts/test/accounts_mixin.py
+++ b/erpnext/accounts/test/accounts_mixin.py
@@ -60,7 +60,6 @@
 		self.income_account = "Sales - " + abbr
 		self.expense_account = "Cost of Goods Sold - " + abbr
 		self.debit_to = "Debtors - " + abbr
-		self.debit_usd = "Debtors USD - " + abbr
 		self.cash = "Cash - " + abbr
 		self.creditors = "Creditors - " + abbr
 		self.retained_earnings = "Retained Earnings - " + abbr
@@ -105,6 +104,28 @@
 				new_acc.save()
 				setattr(self, acc.attribute_name, new_acc.name)
 
+	def create_usd_receivable_account(self):
+		account_name = "Debtors USD"
+		if not frappe.db.get_value(
+			"Account", filters={"account_name": account_name, "company": self.company}
+		):
+			acc = frappe.new_doc("Account")
+			acc.account_name = account_name
+			acc.parent_account = "Accounts Receivable - " + self.company_abbr
+			acc.company = self.company
+			acc.account_currency = "USD"
+			acc.account_type = "Receivable"
+			acc.insert()
+		else:
+			name = frappe.db.get_value(
+				"Account",
+				filters={"account_name": account_name, "company": self.company},
+				fieldname="name",
+				pluck=True,
+			)
+			acc = frappe.get_doc("Account", name)
+		self.debtors_usd = acc.name
+
 	def clear_old_entries(self):
 		doctype_list = [
 			"GL Entry",
@@ -113,6 +134,8 @@
 			"Purchase Invoice",
 			"Payment Entry",
 			"Journal Entry",
+			"Sales Order",
+			"Exchange Rate Revaluation",
 		]
 		for doctype in doctype_list:
 			qb.from_(qb.DocType(doctype)).delete().where(qb.DocType(doctype).company == self.company).run()