fix: test for sales order, pick list and sales invoice

[imdadhussain]

Task ID: https://bloomstack.com/desk#Form/Task/TASK-2021-00345

• Fixes

Description:

1. In Sales Order Test cases there is Permission error validation
2. In Sales Order In items Details object set None value.
3. In Pick List Test cases warehouses name error.
4. In Sales Invoice Test Cases Some are Item Code related Issue.
5. In AccountingDimension Test Cases ValidationError Raise error.
6. In Invoice Discounting Test Cases Some are Item Code related Issue.

Tested: YES

List of Test cases Solved:

- test_request_for_raw_materials (erpnext.selling.doctype.sales_order.test_sales_order.TestSalesOrder)
- test_warehouse_user (erpnext.selling.doctype.sales_order.test_sales_order.TestSalesOrder)
-  test_update_child_qty_rate_perm (erpnext.selling.doctype.sales_order.test_sales_order.TestSalesOrder)
- test_serial_no_based_delivery (erpnext.selling.doctype.sales_order.test_sales_order.TestSalesOrder)
- test_pick_list_for_items_from_multiple_sales_orders (erpnext.stock.doctype.pick_list.test_pick_list.TestPickList)
- test_pick_list_picks_warehouse_for_each_item (erpnext.stock.doctype.pick_list.test_pick_list.TestPickList)
- test_pick_list_shows_serial_no_for_serialized_item (erpnext.stock.doctype.pick_list.test_pick_list.TestPickList)
- test_pp_to_mr_customer_provided (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan)
- test_production_plan (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan)
- test_production_plan_for_existing_ordered_qty (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan) 
- test_production_plan_with_non_stock_item (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan)
- test_production_plan_without_multi_level (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan)
- test_production_plan_without_multi_level_for_existing_ordered_qty (erpnext.manufacturing.doctype.production_plan.test_production_plan.TestProductionPlan)
- test_create_so_with_margin (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_return_sales_invoice (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice) 
- test_rounding_adjustment_2 (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_for_disable_allow_cost_center_in_entry_of_bs_account (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_for_enable_allow_cost_center_in_entry_of_bs_account (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_gl_entry_with_perpetual_inventory_no_item_code (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_gl_entry_with_perpetual_inventory_non_stock_item (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_gl_entry_without_perpetual_inventory (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_with_advance (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_serialized (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_serialized_cancel (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_sales_invoice_with_discount_and_inclusive_tax (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_serial_numbers_against_delivery_note (erpnext.accounts.doctype.sales_invoice.test_sales_invoice.TestSalesInvoice)
- test_make_payment_before_after_period (erpnext.accounts.doctype.invoice_discounting.test_invoice_discounting.TestInvoiceDiscounting)
- test_make_payment_before_loan_period (erpnext.accounts.doctype.invoice_discounting.test_invoice_discounting.TestInvoiceDiscounting)
- test_mandatory (erpnext.accounts.doctype.accounting_dimension.test_accounting_dimension.TestAccountingDimension)

Trackback/Screenshot::
Sales Order Test

    **Pick List  Test**

Sales Invoice Test Cases

1. 
2. 
3. 
4. 
5. 
6. 
7. 
8. 

Invoice Discounting

Accounting Dimension

[vishdha]

@imdad can you add traceback in the description

[Anurag810]

Please update the description as per the template. it should be like a non-functional guy can also undestand.