# Test Error State > Test isFailed() and UserException handling to verify error states work correctly Use when this capability is needed. - Skill: `tomevault-io/test-error-state` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/test-error-state` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/test-error-state/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/test-error-state --- # Test Error State (isFailed) This skill tests `isFailed()` and `UserException` handling in Cubit methods. ## What This Skill Does Tests that: - `isFailed()` returns true after operation fails - `getException()` returns the thrown exception - Error state clears when operation succeeds ## Instructions ### Step 1: Test Error State ```dart import 'package:bloc_superpowers/bloc_superpowers.dart'; import 'package:flutter_test/flutter_test.dart'; import 'package:mocktail/mocktail.dart'; void main() { late UserCubit cubit; late MockApi mockApi; setUp(() { Superpowers.clear(); mockApi = MockApi(); cubit = UserCubit(api: mockApi); }); tearDown(() => cubit.close()); test('isFailed is true after error', () async { when(() => mockApi.getUser()).thenThrow(Exception('Network error')); cubit.loadUser(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(UserCubit), isTrue); }); } ``` ### Step 2: Test Exception Retrieval ```dart test('getException returns the thrown exception', () async { when(() => mockApi.getUser()).thenThrow( UserException('User not found'), ); cubit.loadUser(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(UserCubit), isTrue); final exception = Superpowers.getException(UserCubit); expect(exception, isA()); expect(exception?.message, 'User not found'); }); ``` ### Step 3: Test Error Clears on Success ```dart test('error clears when operation succeeds', () async { // First call fails when(() => mockApi.getUser()).thenThrow(Exception('Network error')); cubit.loadUser(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(UserCubit), isTrue); // Second call succeeds when(() => mockApi.getUser()).thenAnswer((_) async => User(name: 'John')); cubit.loadUser(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(UserCubit), isFalse); expect(Superpowers.getException(UserCubit), isNull); }); ``` ## Testing Different Error Types ### UserException ```dart test('UserException is preserved', () async { when(() => mockApi.getUser()).thenThrow( UserException('Please check your connection'), ); cubit.loadUser(); await Future.delayed(Duration.zero); final exception = Superpowers.getException(UserCubit); expect(exception?.message, 'Please check your connection'); }); ``` ### Exception Converted by catchError ```dart test('exception is converted by catchError', () async { // Cubit has catchError that converts exceptions when(() => mockApi.getUser()).thenThrow(SocketException('No internet')); cubit.loadUser(); await Future.delayed(Duration.zero); final exception = Superpowers.getException(UserCubit); // catchError converted it to UserException expect(exception?.message, contains('connection')); }); ``` ### With Composite Keys ```dart test('error state with composite key', () async { when(() => mockApi.deleteItem('123')).thenThrow( UserException('Cannot delete item'), ); cubit.deleteItem('123'); await Future.delayed(Duration.zero); // Error is tracked per item expect(Superpowers.isFailed((DeleteItem, '123')), isTrue); expect(Superpowers.isFailed((DeleteItem, '456')), isFalse); final exception = Superpowers.getException((DeleteItem, '123')); expect(exception?.message, 'Cannot delete item'); }); ``` ## Testing Error Recovery ```dart test('manual clearException works', () async { when(() => mockApi.getUser()).thenThrow(Exception('Error')); cubit.loadUser(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(UserCubit), isTrue); // Manually clear the exception Superpowers.clearException(UserCubit); expect(Superpowers.isFailed(UserCubit), isFalse); expect(Superpowers.getException(UserCubit), isNull); }); ``` ## Testing with Retry ```dart test('error only set after all retries exhausted', () async { var callCount = 0; when(() => mockApi.getUser()).thenAnswer((_) { callCount++; throw Exception('Retry $callCount'); }); cubit.loadUserWithRetry(); // mix with retry: retry(maxRetries: 2) await Future.delayed(const Duration(seconds: 5)); // Wait for retries expect(Superpowers.isFailed(UserCubit), isTrue); expect(callCount, 3); // Initial + 2 retries }); ``` ## Complete Test File ```dart import 'dart:async'; import 'package:bloc_superpowers/bloc_superpowers.dart'; import 'package:flutter_test/flutter_test.dart'; import 'package:mocktail/mocktail.dart'; class MockApi extends Mock implements Api {} void main() { late ProductCubit cubit; late MockApi mockApi; setUp(() { Superpowers.clear(); mockApi = MockApi(); cubit = ProductCubit(api: mockApi); }); tearDown(() => cubit.close()); group('error state', () { test('isFailed is true after error', () async { when(() => mockApi.getProducts()).thenThrow(Exception('Error')); cubit.loadProducts(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(ProductCubit), isTrue); expect(Superpowers.isWaiting(ProductCubit), isFalse); }); test('getException returns UserException', () async { when(() => mockApi.getProducts()).thenThrow( UserException('Products not available'), ); cubit.loadProducts(); await Future.delayed(Duration.zero); final exception = Superpowers.getException(ProductCubit); expect(exception, isA()); expect(exception?.message, 'Products not available'); }); test('error clears on successful retry', () async { // First fails when(() => mockApi.getProducts()).thenThrow(Exception('Error')); cubit.loadProducts(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(ProductCubit), isTrue); // Then succeeds when(() => mockApi.getProducts()).thenAnswer( (_) async => [Product(id: '1', name: 'Widget')], ); cubit.loadProducts(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(ProductCubit), isFalse); expect(cubit.state.products.length, 1); }); test('per-item error state', () async { when(() => mockApi.deleteProduct('1')).thenThrow( UserException('Cannot delete'), ); cubit.deleteProduct('1'); await Future.delayed(Duration.zero); expect(Superpowers.isFailed((DeleteProduct, '1')), isTrue); expect(Superpowers.isFailed((DeleteProduct, '2')), isFalse); final exception = Superpowers.getException((DeleteProduct, '1')); expect(exception?.message, 'Cannot delete'); }); test('clearException manually clears error', () async { when(() => mockApi.getProducts()).thenThrow(Exception('Error')); cubit.loadProducts(); await Future.delayed(Duration.zero); expect(Superpowers.isFailed(ProductCubit), isTrue); Superpowers.clearException(ProductCubit); expect(Superpowers.isFailed(ProductCubit), isFalse); expect(Superpowers.getException(ProductCubit), isNull); }); }); } ``` ## Key Points 1. **Use `Superpowers.isFailed(key)`** to check error state 2. **Use `Superpowers.getException(key)`** to get the exception 3. **Use `Superpowers.clearException(key)`** to manually clear 4. **Error clears automatically** when operation succeeds 5. **Match the key exactly** as used in the Cubit's `mix()` call 6. **Reset with `Superpowers.clear()`** in setUp --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/marcglasberg) — claim your Tome and manage your conversions.