Error Testing in JavaScript

1// Method 1: Test error throwing
2function testErrorThrowing() {
3    try {
4        throw new Error('Test error');
5        return false; // Should not reach here
6    } catch (error) {
7        return error.message === 'Test error';
8    }
9}
10
11console.log('Error test:', testErrorThrowing());
12
13// Method 2: Test error types
14function testErrorType() {
15    try {
16        throw new TypeError('Type error');
17    } catch (error) {
18        return error instanceof TypeError;
19    }
20}
21
22// Method 3: Mock error scenarios
23function createErrorScenario(type) {
24    switch (type) {
25        case 'network':
26            throw new Error('Network error');
27        case 'timeout':
28            throw new Error('Timeout');
29        case 'validation':
30            throw new ValidationError('Invalid input');
31        default:
32            throw new Error('Unknown error');
33    }
34}
35
36// Method 4: Error assertion helper
37function assertError(fn, expectedError) {
38    try {
39        fn();
40        return false; // Should have thrown
41    } catch (error) {
42        if (expectedError) {
43            return error instanceof expectedError;
44        }
45        return true; // Any error is fine
46    }
47}
48
49assertError(() => {
50    throw new TypeError('Type error');
51}, TypeError);
52
53// Method 5: Async error testing
54async function testAsyncError() {
55    try {
56        await Promise.reject(new Error('Async error'));
57        return false;
58    } catch (error) {
59        return error.message === 'Async error';
60    }
61}
62
63// Method 6: Error boundary testing
64function testErrorBoundary(errorBoundary, errorFn) {
65    try {
66        errorFn();
67    } catch (error) {
68        errorBoundary.catchError(error, { component: 'TestComponent' });
69    }
70    return errorBoundary.getErrors().length > 0;
71}
72
73// Method 7: Integration error testing
74async function testErrorHandling() {
75    const scenarios = [
76        () => { throw new Error('Error 1'); },
77        () => { throw new TypeError('Error 2'); },
78        () => { throw new ReferenceError('Error 3'); }
79    ];
80    
81    const results = scenarios.map(scenario => {
82        try {
83            scenario();
84            return { passed: false };
85        } catch (error) {
86            return { passed: true, error: error.name };
87        }
88    });
89    
90    return results;
91}