test(model): add workbook, dependency and json tests

test/workbook_test.dart

@@ -0,0 +1,116 @@
+import 'package:cellar/cellar.dart';
+import 'package:test/test.dart';
+
+double numberOf(CellValue value) => (value as NumberValue).value;
+
+void main() {
+  group('multi-sheet workbook', () {
+    test('a workbook holds several named sheets', () {
+      final workbook = Workbook();
+      workbook.addSheet('Sheet1');
+      workbook.addSheet('Data');
+      expect(workbook.sheetCount, 2);
+      expect(workbook.sheetNames, ['Sheet1', 'Data']);
+    });
+
+    test('cross sheet reference resolves the other sheet', () {
+      final workbook = Workbook();
+      final first = workbook.addSheet('Sheet1');
+      final data = workbook.addSheet('Data');
+      first.setValue('A1', '10');
+      first.setValue('A2', '20');
+      data.setValue('B1', '=Sheet1!A1 + Sheet1!A2');
+      expect(numberOf(data.valueOf('B1')), 30);
+    });
+
+    test('cross sheet range aggregation', () {
+      final workbook = Workbook();
+      final first = workbook.addSheet('Sheet1');
+      final data = workbook.addSheet('Data');
+      first.setValue('A1', '1');
+      first.setValue('A2', '2');
+      first.setValue('A3', '3');
+      data.setValue('B1', '=SUM(Sheet1!A1:A3) * 2');
+      expect(numberOf(data.valueOf('B1')), 12);
+    });
+
+    test('editing a precedent recomputes a dependent on another sheet', () {
+      final workbook = Workbook();
+      final first = workbook.addSheet('Sheet1');
+      final data = workbook.addSheet('Data');
+      first.setValue('A1', '5');
+      data.setValue('B1', '=Sheet1!A1 * 3');
+      expect(numberOf(data.valueOf('B1')), 15);
+      first.setValue('A1', '9');
+      expect(numberOf(data.valueOf('B1')), 27);
+    });
+
+    test('quoted sheet names with spaces', () {
+      final workbook = Workbook();
+      final first = workbook.addSheet('My Sheet');
+      final data = workbook.addSheet('Data');
+      first.setValue('A1', '42');
+      data.setValue('B1', "='My Sheet'!A1 + 1");
+      expect(numberOf(data.valueOf('B1')), 43);
+    });
+
+    test('reference to an unknown sheet is #REF!', () {
+      final workbook = Workbook();
+      final data = workbook.addSheet('Data');
+      data.setValue('A1', '=Missing!A1');
+      expect(data.valueOf('A1'), const ErrorValue(ErrorKind.ref));
+    });
+
+    test('a cycle spanning two sheets is detected', () {
+      final workbook = Workbook();
+      final first = workbook.addSheet('Sheet1');
+      final data = workbook.addSheet('Data');
+      first.setValue('A1', '=Data!A1');
+      data.setValue('A1', '=Sheet1!A1');
+      expect(first.valueOf('A1'), const ErrorValue(ErrorKind.cycle));
+      expect(data.valueOf('A1'), const ErrorValue(ErrorKind.cycle));
+    });
+  });
+
+  group('named ranges', () {
+    test('a named cell resolves to its value', () {
+      final workbook = Workbook();
+      final sheet = workbook.addSheet('Sheet1');
+      sheet.setValue('B2', '99');
+      workbook.defineName('Answer', 'Sheet1!B2');
+      sheet.setValue('C1', '=Answer + 1');
+      expect(numberOf(sheet.valueOf('C1')), 100);
+    });
+
+    test('a named range works inside an aggregate', () {
+      final workbook = Workbook();
+      final sheet = workbook.addSheet('Sheet1');
+      sheet.setValue('A1', '10');
+      sheet.setValue('A2', '20');
+      sheet.setValue('A3', '30');
+      workbook.defineName('Inputs', 'Sheet1!A1:A3');
+      sheet.setValue('B1', '=SUM(Inputs)');
+      expect(numberOf(sheet.valueOf('B1')), 60);
+    });
+
+    test('a named range defined after the formula still propagates', () {
+      final workbook = Workbook();
+      final sheet = workbook.addSheet('Sheet1');
+      sheet.setValue('A1', '5');
+      sheet.setValue('A2', '7');
+      sheet.setValue('B1', '=SUM(Prices)');
+      expect(sheet.valueOf('B1'), const ErrorValue(ErrorKind.name));
+      workbook.defineName('Prices', 'Sheet1!A1:A2');
+      expect(numberOf(sheet.valueOf('B1')), 12);
+      sheet.setValue('A1', '50');
+      expect(numberOf(sheet.valueOf('B1')), 57);
+    });
+
+    test('an unknown bare name is #NAME?', () {
+      final workbook = Workbook();
+      final sheet = workbook.addSheet('Sheet1');
+      sheet.setValue('A1', '=Nope + 1');
+      expect(sheet.valueOf('A1'), const ErrorValue(ErrorKind.name));
+    });
+  });
+}