The spreadsheet has numbered rows (0 -> 99) and lettered columns (a-z).
If a value (int, float, string) is entered into a cell, it becomes the
value of that cell.
If a formula is entered into a cell, the value obtained by evaluating
that formula becomes the value of that cell.
Formulas are marked by beginning with an "=".
Formulas may refer cells by ColumLetterRowNumber (=A42+B19 etc).
Whenever a cell is updated, all formula cells which depend on that cell
are updated.
Minimally, the formula language supports +,-,* (multiplication),/ (division),
( ) (brackets), in infix notation.
Value and formula cells are visually distinct.
There is some mechanism which allows the user to view the formula
associated with a formula cell.
You do not have to check for invalid formulas,invalid numbers, circular definitions etc. in calculations.
What is tested: Complex GUI elements, GUI navigation, Formula evaluation.
Contributed by Stevan Apter, sa at nsl.com