Initial commit

test/calculator_logic_test.dart

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+import 'package:flutter_test/flutter_test.dart';
+import 'package:kalkulator/calculator_logic.dart';
+
+void main() {
+  late CalculatorLogic calc;
+
+  setUp(() {
+    calc = CalculatorLogic();
+  });
+
+  group('inputDigit', () {
+    test('starts with 0', () {
+      expect(calc.display, '0');
+    });
+
+    test('replaces initial 0 with digit', () {
+      calc.inputDigit('5');
+      expect(calc.display, '5');
+    });
+
+    test('appends digits', () {
+      calc.inputDigit('1');
+      calc.inputDigit('2');
+      calc.inputDigit('3');
+      expect(calc.display, '123');
+    });
+  });
+
+  group('inputDecimal', () {
+    test('adds decimal point', () {
+      calc.inputDigit('3');
+      calc.inputDecimal();
+      expect(calc.display, '3.');
+    });
+
+    test('ignores second decimal point', () {
+      calc.inputDigit('3');
+      calc.inputDecimal();
+      calc.inputDigit('1');
+      calc.inputDecimal();
+      expect(calc.display, '3.1');
+    });
+  });
+
+  group('addition', () {
+    test('2 + 3 = 5', () {
+      calc.inputDigit('2');
+      calc.inputOperator('+');
+      calc.inputDigit('3');
+      calc.calculate();
+      expect(calc.display, '5');
+    });
+  });
+
+  group('subtraction', () {
+    test('9 - 4 = 5', () {
+      calc.inputDigit('9');
+      calc.inputOperator('-');
+      calc.inputDigit('4');
+      calc.calculate();
+      expect(calc.display, '5');
+    });
+  });
+
+  group('multiplication', () {
+    test('6 * 7 = 42', () {
+      calc.inputDigit('6');
+      calc.inputOperator('*');
+      calc.inputDigit('7');
+      calc.calculate();
+      expect(calc.display, '42');
+    });
+  });
+
+  group('division', () {
+    test('8 / 2 = 4', () {
+      calc.inputDigit('8');
+      calc.inputOperator('/');
+      calc.inputDigit('2');
+      calc.calculate();
+      expect(calc.display, '4');
+    });
+
+    test('division by zero returns Infinity', () {
+      calc.inputDigit('5');
+      calc.inputOperator('/');
+      calc.inputDigit('0');
+      calc.calculate();
+      expect(calc.display, 'Infinity');
+    });
+
+    test('decimal result: 7 / 2 = 3.5', () {
+      calc.inputDigit('7');
+      calc.inputOperator('/');
+      calc.inputDigit('2');
+      calc.calculate();
+      expect(calc.display, '3.5');
+    });
+  });
+
+  group('chained operations', () {
+    test('2 + 3 + 4 = 9', () {
+      calc.inputDigit('2');
+      calc.inputOperator('+');
+      calc.inputDigit('3');
+      calc.inputOperator('+');
+      expect(calc.display, '5');
+      calc.inputDigit('4');
+      calc.calculate();
+      expect(calc.display, '9');
+    });
+  });
+
+  group('clear', () {
+    test('resets to 0', () {
+      calc.inputDigit('5');
+      calc.inputOperator('+');
+      calc.inputDigit('3');
+      calc.clear();
+      expect(calc.display, '0');
+    });
+  });
+
+  group('toggleSign', () {
+    test('positive to negative', () {
+      calc.inputDigit('7');
+      calc.toggleSign();
+      expect(calc.display, '-7');
+    });
+
+    test('negative to positive', () {
+      calc.inputDigit('7');
+      calc.toggleSign();
+      calc.toggleSign();
+      expect(calc.display, '7');
+    });
+  });
+
+  group('percent', () {
+    test('50 percent = 0.5', () {
+      calc.inputDigit('5');
+      calc.inputDigit('0');
+      calc.percent();
+      expect(calc.display, '0.5');
+    });
+  });
+}