While we might never be able to have 100% of our code strict, we can at
the very least do it for all of our tests. This ensures that our tests
are using our API with the types as intended by the test author, and not
silently be cast to what our API requires.
In cells with formulas containing conditions like `=IFSUM(A1:A3;"";B1:B3)`
to sum cells from range A1:A3 with empty value in range B1:B3, the function
`Functions::ifCondition()` create in this case the code `=""""` instead of
`=""`, so it didn't work.
Closes#1206
Conditional operators in the selection parameter of COUNTIF
functions were not being parsed properly, causing evaluations
of formulae with such functions to sometimes fail.
Fixes#526Closes#528