customer.json -- a checkbox field is added which gives user ability to bypass credit limit check at sales order level for a customer. It is default to 0. Also patch is added to update value of new field to 0 after migrate.
test_customer.js -- It is auto generated file as customer.json is modified. And it is removed.
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index fd7a1b4..41999a9 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -455,3 +455,4 @@
 erpnext.patches.v9_0.set_variant_item_description
 erpnext.patches.v9_0.set_uoms_in_variant_field
 erpnext.patches.v9_0.copy_old_fees_field_data
+erpnext.patches.v9_0.set_bypasscreditlimitcheckatsalesorder_in_customer
diff --git a/erpnext/patches/v9_0/set_bypasscreditlimitcheckatsalesorder_in_customer.py b/erpnext/patches/v9_0/set_bypasscreditlimitcheckatsalesorder_in_customer.py
new file mode 100644
index 0000000..e94a508
--- /dev/null
+++ b/erpnext/patches/v9_0/set_bypasscreditlimitcheckatsalesorder_in_customer.py
@@ -0,0 +1,10 @@
+import frappe
+
+def execute():
+	frappe.reload_doctype("Customer")
+	
+	if "bypass_credit_limit_check_at_sales_order" in frappe.db.get_table_columns("Customer"):
+		frappe.db.sql("""
+			update `tabCustomer`
+			set bypass_credit_limit_check_at_sales_order = 0
+			where (bypass_credit_limit_check_at_sales_order is NULL)""")
\ No newline at end of file
diff --git a/erpnext/selling/doctype/customer/customer.json b/erpnext/selling/doctype/customer/customer.json
index f231b85..24b1968 100644
--- a/erpnext/selling/doctype/customer/customer.json
+++ b/erpnext/selling/doctype/customer/customer.json
@@ -913,6 +913,7 @@
    "bold": 0, 
    "collapsible": 0, 
    "columns": 0, 
+   "default": "0", 
    "fieldname": "bypass_credit_limit_check_at_sales_order", 
    "fieldtype": "Check", 
    "hidden": 0, 
@@ -1232,7 +1233,7 @@
  "issingle": 0, 
  "istable": 0, 
  "max_attachments": 0, 
- "modified": "2017-10-24 14:44:48.508334", 
+ "modified": "2017-10-26 16:21:18.028471", 
  "modified_by": "Administrator", 
  "module": "Selling", 
  "name": "Customer", 
diff --git a/erpnext/selling/doctype/customer/test_customer.js b/erpnext/selling/doctype/customer/test_customer.js
deleted file mode 100644
index 65b81af..0000000
--- a/erpnext/selling/doctype/customer/test_customer.js
+++ /dev/null
@@ -1,23 +0,0 @@
-/* eslint-disable */
-// rename this file from _test_[name] to test_[name] to activate
-// and remove above this line
-
-QUnit.test("test: Customer", function (assert) {
-	let done = assert.async();
-
-	// number of asserts
-	assert.expect(1);
-
-	frappe.run_serially([
-		// insert a new Customer
-		() => frappe.tests.make('Customer', [
-			// values to be set
-			{key: 'value'}
-		]),
-		() => {
-			assert.equal(cur_frm.doc.key, 'value');
-		},
-		() => done()
-	]);
-
-});