testInventory: small cleanups

move asset price valuation tests in a dedicated test class

remove unused variables
Status Job ID Name Coverage
  External
passed ERP5.CodingStyleTest-TestRunner1

05:37:17

passed ERP5.PerformanceTest-TestRunner1

01:22:45

failed ERP5.UnitTest-TestRunner1

01:28:10

passed ERP5.CodingStyleTest-TestRunner1

00:43:36

passed ERP5.PerformanceTest-TestRunner1

00:32:09

canceled ERP5.UnitTest-TestRunner1

failed ERP5.UnitTest-TestRunner1

01:41:40

canceled ERP5.UnitTest-TestRunner1

failed ERP5.UnitTest-TestRunner1

11:12:15

passed ERP5.UnitTest-TestRunner1

01:43:43