test: fix salary component not found; other optimisation (#24920)

diff --git a/erpnext/payroll/doctype/gratuity/test_gratuity.py b/erpnext/payroll/doctype/gratuity/test_gratuity.py
index e89e3dd..7daea2d 100644
--- a/erpnext/payroll/doctype/gratuity/test_gratuity.py
+++ b/erpnext/payroll/doctype/gratuity/test_gratuity.py
@@ -15,9 +15,12 @@
 
 test_dependencies = ["Salary Component", "Salary Slip", "Account"]
 class TestGratuity(unittest.TestCase):
-	def setUp(self):
+	@classmethod
+	def setUpClass(cls):
 		make_earning_salary_component(setup=True, test_tax=True, company_list=['_Test Company'])
 		make_deduction_salary_component(setup=True, test_tax=True, company_list=['_Test Company'])
+
+	def setUp(self):
 		frappe.db.sql("DELETE FROM `tabGratuity`")
 		frappe.db.sql("DELETE FROM `tabAdditional Salary` WHERE ref_doctype = 'Gratuity'")
 
diff --git a/erpnext/payroll/doctype/salary_slip/test_salary_slip.py b/erpnext/payroll/doctype/salary_slip/test_salary_slip.py
index 143a306..7672695 100644
--- a/erpnext/payroll/doctype/salary_slip/test_salary_slip.py
+++ b/erpnext/payroll/doctype/salary_slip/test_salary_slip.py
@@ -361,7 +361,6 @@
 		# as per assigned salary structure 40500 in monthly salary so 236000*5/100/12
 		frappe.db.sql("""delete from `tabPayroll Period`""")
 		frappe.db.sql("""delete from `tabSalary Component`""")
-		frappe.db.sql("""delete from `tabAdditional Salary`""")
 
 		payroll_period = create_payroll_period()
 
diff --git a/erpnext/projects/doctype/timesheet/test_timesheet.py b/erpnext/projects/doctype/timesheet/test_timesheet.py
index f93c6be..f7c764e 100644
--- a/erpnext/projects/doctype/timesheet/test_timesheet.py
+++ b/erpnext/projects/doctype/timesheet/test_timesheet.py
@@ -13,9 +13,18 @@
 from erpnext.accounts.doctype.sales_invoice.test_sales_invoice import create_sales_invoice
 from erpnext.payroll.doctype.salary_structure.test_salary_structure \
 	import make_salary_structure, create_salary_structure_assignment
+from erpnext.payroll.doctype.salary_slip.test_salary_slip import (
+	make_earning_salary_component,
+	make_deduction_salary_component
+)
 from erpnext.hr.doctype.employee.test_employee import make_employee
 
 class TestTimesheet(unittest.TestCase):
+	@classmethod
+	def setUpClass(cls):
+		make_earning_salary_component(setup=True, company_list=['_Test Company'])
+		make_deduction_salary_component(setup=True, company_list=['_Test Company'])
+
 	def setUp(self):
 		for dt in ["Salary Slip", "Salary Structure", "Salary Structure Assignment", "Timesheet"]:
 			frappe.db.sql("delete from `tab%s`" % dt)