test(io): add csv, format and table tests

test/csv_test.dart

@@ -0,0 +1,60 @@
+import 'package:cellar/cellar.dart';
+import 'package:test/test.dart';
+
+double numberOf(CellValue value) => (value as NumberValue).value;
+
+void main() {
+  group('csv parsing', () {
+    test('parses quoted fields with embedded commas and quotes', () {
+      final rows = parseCsv('a,"b,c","he said ""hi"""\n1,2,3');
+      expect(rows, [
+        ['a', 'b,c', 'he said "hi"'],
+        ['1', '2', '3'],
+      ]);
+    });
+
+    test('a trailing newline does not create an empty record', () {
+      final rows = parseCsv('a,b\nc,d\n');
+      expect(rows.length, 2);
+    });
+  });
+
+  group('csv import and compute', () {
+    test('imports literals and formulas then computes', () {
+      final sheet = Sheet();
+      importCsv(sheet, 'Name,Qty,Price,Total\nApple,3,2,=B2*C2\nPear,4,5,=B3*C3\n,,,=SUM(D2:D3)');
+      expect(numberOf(sheet.valueOf('D2')), 6);
+      expect(numberOf(sheet.valueOf('D3')), 20);
+      expect(numberOf(sheet.valueOf('D4')), 26);
+    });
+  });
+
+  group('csv round trip', () {
+    test('formulas survive export and re-import with equal results', () {
+      final original = Sheet();
+      original.setValue('A1', '10');
+      original.setValue('A2', '20');
+      original.setValue('A3', '30');
+      original.setValue('B1', '=SUM(A1:A3)');
+      original.setValue('B2', '=AVERAGE(A1:A3)');
+      original.setValue('B3', '=IF(B1>50, "high", "low")');
+
+      final formulaCsv = exportFormulas(original);
+      final reloaded = Sheet();
+      importCsv(reloaded, formulaCsv);
+
+      expect(exportFormulas(reloaded), formulaCsv);
+      expect(numberOf(reloaded.valueOf('B1')), 60);
+      expect(numberOf(reloaded.valueOf('B2')), 20);
+      expect(reloaded.valueOf('B3'), const TextValue('high'));
+    });
+
+    test('value export renders computed numbers', () {
+      final sheet = Sheet();
+      sheet.setValue('A1', '4');
+      sheet.setValue('B1', '=A1*A1');
+      final valueCsv = exportValues(sheet);
+      expect(valueCsv, '4,16');
+    });
+  });
+}

test/format_test.dart

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+import 'package:cellar/cellar.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('number format', () {
+    test('grouped decimals', () {
+      const format = NumberFormat.decimal(decimals: 2, thousands: true);
+      expect(format.apply(const NumberValue(1234567.891)), '1,234,567.89');
+      expect(format.apply(const NumberValue(-5.5)), '-5.50');
+    });
+
+    test('percent scales by a hundred', () {
+      const format = NumberFormat.percent(decimals: 1);
+      expect(format.apply(const NumberValue(0.1234)), '12.3%');
+    });
+
+    test('currency before and after', () {
+      const before = NumberFormat.currency(r'$', decimals: 2);
+      const after = NumberFormat.currency('zl', decimals: 2, before: false, thousands: false);
+      expect(before.apply(const NumberValue(1234.5)), r'$1,234.50');
+      expect(after.apply(const NumberValue(30)), '30.00zl');
+    });
+
+    test('integer with thousands', () {
+      const format = NumberFormat.integer(thousands: true);
+      expect(format.apply(const NumberValue(1234567)), '1,234,567');
+    });
+
+    test('non-number values fall through to display', () {
+      const format = NumberFormat.decimal(decimals: 2);
+      expect(format.apply(const TextValue('hello')), 'hello');
+      expect(format.apply(const ErrorValue(ErrorKind.divZero)), '#DIV/0!');
+    });
+
+    test('fromCode parses common patterns', () {
+      expect(NumberFormat.fromCode('#,##0.00').apply(const NumberValue(1234.5)), '1,234.50');
+      expect(NumberFormat.fromCode('0.0%').apply(const NumberValue(0.25)), '25.0%');
+      expect(NumberFormat.fromCode(r'$#,##0.00').apply(const NumberValue(1234.5)), r'$1,234.50');
+    });
+
+    test('toCode round trips', () {
+      expect(const NumberFormat.decimal(decimals: 2, thousands: true).toCode(), '#,##0.00');
+      expect(const NumberFormat.percent(decimals: 1).toCode(), '0.0%');
+      expect(const NumberFormat.integer(thousands: true).toCode(), '#,##0');
+    });
+  });
+}

test/table_test.dart

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+import 'package:cellar/cellar.dart';
+import 'package:test/test.dart';
+
+double num(CellValue value) => (value as NumberValue).value;
+
+Sheet salesSheet() {
+  final sheet = Sheet();
+  final rows = [
+    ['Region', 'Product', 'Amount'],
+    ['North', 'A', '100'],
+    ['South', 'A', '150'],
+    ['North', 'B', '200'],
+    ['South', 'B', '50'],
+    ['North', 'A', '75'],
+  ];
+  for (var r = 0; r < rows.length; r++) {
+    for (var c = 0; c < rows[r].length; c++) {
+      sheet.setCell(CellAddress(c, r), rows[r][c]);
+    }
+  }
+  return sheet;
+}
+
+void main() {
+  group('data table', () {
+    test('reads a header row from a sheet', () {
+      final table = DataTable.fromSheet(salesSheet());
+      expect(table.headers, ['Region', 'Product', 'Amount']);
+      expect(table.rowCount, 5);
+    });
+
+    test('sortBy descending', () {
+      final sorted = DataTable.fromSheet(salesSheet()).sortBy('Amount', ascending: false);
+      expect(num(sorted.cell(0, 'Amount')), 200);
+      expect(num(sorted.cell(4, 'Amount')), 50);
+    });
+
+    test('filter by a column predicate', () {
+      final filtered = DataTable.fromSheet(salesSheet())
+          .where('Region', (value) => value.display() == 'North');
+      expect(filtered.rowCount, 3);
+    });
+
+    test('groupBy with sum and count aggregations', () {
+      final grouped = DataTable.fromSheet(salesSheet()).groupBy(
+        ['Region'],
+        const [
+          Aggregation('Amount', Aggregator.sum, 'Total'),
+          Aggregation('Amount', Aggregator.count, 'Lines'),
+        ],
+      );
+      expect(grouped.headers, ['Region', 'Total', 'Lines']);
+      expect(num(grouped.cell(0, 'Total')), 375);
+      expect(num(grouped.cell(0, 'Lines')), 3);
+      expect(num(grouped.cell(1, 'Total')), 200);
+    });
+
+    test('pivot on region by product', () {
+      final pivot = DataTable.fromSheet(salesSheet()).pivot(
+        rowKey: 'Region',
+        columnKey: 'Product',
+        valueColumn: 'Amount',
+      );
+      expect(pivot.rowLabels, ['North', 'South']);
+      expect(pivot.columnLabels, ['A', 'B']);
+      expect(num(pivot.at('North', 'A')), 175);
+      expect(num(pivot.at('South', 'B')), 50);
+    });
+
+    test('selectColumns projects a subset', () {
+      final projected = DataTable.fromSheet(salesSheet()).selectColumns(['Product', 'Amount']);
+      expect(projected.headers, ['Product', 'Amount']);
+      expect(projected.rows.first.length, 2);
+    });
+  });
+}