The tests stay; they just no longer run in separate processes. I think that only 2 tests still require separate processes - Helper/SampleTest and Tcpdf/NoDieTest. Aside from a new internal method in IOFactory, all the changes here are to test members.
Dealing mostly with mixed variable type. In a great many cases, problems can be resolved replacing `getValue` with `getValueString` or `getCalculatedValue` with `getCalculatedValueString`.
Fix#4324. Serialization was explicity forbidden by PR #3199. This was in response to several issues, and concern that the Spreadsheet object contained non-serializable properties. This PR restores the ability to serialize a spreadsheet. Json serialization remains unsupported.
Fix#1757, closed in Nov. 2023 but just reopened. At the time, Cell property `formulaAttributes` was stored as a SimpleXmlElement. Dynamic arrays PR #3962 defined that property as `null|array<string, string>` in the doc block. However, it left the formal Php type for the property as `mixed`. This PR changes the formal type to `?array`.
Fix#1741, closed in Dec. 2020 but just reopened. Calculation property `referenceHelper` was defined as static, and, since static properties don't take part in serialization, this caused a problem after unserialization. There are at least 3 trivial ways to deal with this - make it an instance property, reinitialize it when unserialized using a wakeup method, or remove the property altogether. This PR uses the last of those 3.
Calculation does have other static properties. Almost all of these deal with locale. So serialize/unserialize might wind up using a default locale when non-default is desired (but not necessarily required). If that is a problem for end-users, it will be a new one, and I will work on a solution if and when the time comes.
Static property `returnArrayAsType` is potentially problematic. However, instance property `instanceArrayReturnType` is the preferred method of handling this, and using that will avoid any problems.
Issue #932 also dealt with serialization. I do not have the wherewithal to investigate that issue. If it is not solved by this and the earlier PR's, I will have to leave it to others to re-raise it.
Spreadsheet `copy` is now simplified to use serialize followed by unserialize. Formal tests are added. In addition, I have made a number of informal tests on very complicated spreadsheets, and it has performed correctly for all of them.
oleibman