Error Simulation

The plugin supports error simulation, which allows you to configure error probability and error types for mock requests.

Basic Usage

import { defineMock } from 'vite-plugin-mock-dev-server'

export default defineMock({
  url: '/api/error-simulation',
  method: 'GET',
  body: { success: true, message: 'Request successful' },
  error: {
    probability: 0.5, // 50% probability of error
    status: 500,
  }
})

Configuration Options

error

• Type: MockErrorConfig
• Description: Configure error simulation

MockErrorConfig

Option	Type	Default	Description
probability	number	0.5	Error probability (0-1)
status	number	500	Error status code
statusText	string	-	Error status text
body	ResponseBody | ResponseBodyFn	-	Custom error response body, suitable for when the status is 200, but the response body needs to simulate an error scenario

Examples

Different Error Types

import { defineMock } from 'vite-plugin-mock-dev-server'

export default defineMock([
  {
    url: '/api/error-simulation/404',
    method: 'GET',
    body: { success: true, message: 'Request successful' },
    error: {
      probability: 0.7,
      status: 404,
    }
  },
  {
    url: '/api/error-simulation/text',
    method: 'GET',
    body: 'Request successful',
    type: 'text',
    error: {
      probability: 0.5,
      status: 500,
    }
  }
])

Custom Error Response Body

import { defineMock } from 'vite-plugin-mock-dev-server'

export default defineMock({
  url: '/api/error-simulation/custom-body',
  method: 'GET',
  body: { code: 200, msg: 'Success', result: { data: 'some data' } },
  error: {
    probability: 0.5,
    status: 200, // Network request successful
    body: { code: 500, msg: 'Internal error', result: null } // But returns error data structure
  }
})

Empty Result Simulation

import { defineMock } from 'vite-plugin-mock-dev-server'

export default defineMock({
  url: '/api/error-simulation/empty-result',
  method: 'GET',
  body: { code: 200, msg: 'Success', result: { data: 'some data' } },
  error: {
    probability: 0.5,
    status: 200,
    body: { code: 200, msg: 'Success', result: {} } // Success status but empty result
  }
})

Dynamic Error Response

import { defineMock } from 'vite-plugin-mock-dev-server'

export default defineMock({
  url: '/api/error-simulation/dynamic-body',
  method: 'GET',
  body: { code: 200, msg: 'Success', result: { data: 'some data' } },
  error: {
    probability: 0.5,
    status: 200,
    body: (request) => {
      // Dynamically generate error response based on request parameters
      return {
        code: 500,
        msg: `Error for request: ${request.query.id || 'unknown'}`,
        result: null
      }
    }
  }
})

Why Use Error Simulation?

Error simulation is useful in the following scenarios:

• Testing Error Handling: Verify that your application correctly handles error responses from the server.
• Simulating Network Issues: Test how your application behaves when the server is unavailable or responds with errors.
• Enhancing Test Coverage: Increase the coverage of your tests by simulating a variety of error scenarios.
• Retry Mechanisms: Test how your application handles retries when errors occur.
• Probability Control: Use the probability option to control the likelihood of errors occurring, allowing for more realistic testing scenarios.