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Non-Retrying Assertions

Non-retrying assertions are synchronous assertions that allow to test any conditions, but do not auto-retry. They are ideal for testing static values, API responses, and any scenario where the expected condition should be true at the moment of evaluation.

Non-retrying assertions differ from retrying assertions in that they:

  • Evaluate immediately - They check the condition once and return the result
  • Are synchronous - They don’t need to be awaited and return results immediately
  • Have no timeout behavior - They either pass or fail instantly
  • Are ideal for static content - Perfect for testing values that don’t change over time
JavaScript 
import http from 'k6/http';
import { expect } from 'https://jslib.k6.io/k6-testing/0.5.0/index.js';

export default function () {
  const response = http.get('https://quickpizza.grafana.com/');

  // Immediate assertions
  expect(response.status).toBe(200);
  expect(response.body).toBeDefined();
  expect(response.body).toBeTruthy();
  expect(typeof response.body).toBe('string');
  expect(response.body).toContain('Pizza');
}

When to Use Non-Retrying Assertions

Non-retrying assertions are best suited for:

  • API response testing - Checking status codes, response data, headers
  • Static values - Testing constants, configuration values, or computed results
  • Data validation - Verifying object properties, array contents, or data types
  • Known state verification - Checking values that should be immediately available

Non-retrying assertions methods

Equality Assertions

MethodDescription
toBe()Exact equality using Object.is()
toEqual()Deep equality comparison

Truthiness Assertions

MethodDescription
toBeTruthy()Value is truthy
toBeFalsy()Value is falsy
toBeDefined()Value is not undefined
toBeUndefined()Value is undefined
toBeNull()Value is null

Comparison Assertions

MethodDescription
toBeGreaterThan()Numeric greater than
toBeGreaterThanOrEqual()Numeric greater than or equal
toBeLessThan()Numeric less than
toBeLessThanOrEqual()Numeric less than or equal
toBeCloseTo()Floating point comparison

Collection Assertions

MethodDescription
toContain()Array/string contains value
toContainEqual()Array contains object with matching content
toHaveLength()Array/string has specific length

Property Assertions

MethodDescription
toHaveProperty()Object has specific property

Type Assertions

MethodDescription
toBeInstanceOf()Value is instance of class

Common Patterns

API Response Validation

JavaScript 
export default function () {
  const response = http.get('https://quickpizza.grafana.com/');

  // Response status and headers
  expect(response.status).toBe(200);
  expect(response.headers['content-type']).toContain('text/html');

  // Response data structure
  expect(response.body).toBeDefined();
  expect(response.body).toBeTruthy();
  expect(response.body).toContain('pizza');
  expect(response.body).toContain('Pizza');

  // Data types
  expect(typeof response.body).toBe('string');
  expect(response.body.length).toBeGreaterThan(0);
}

Data Validation

JavaScript 
export default function () {
  const userData = {
    name: 'John Doe',
    email: 'john@example.com',
    age: 30,
    hobbies: ['reading', 'gaming'],
    address: {
      city: 'New York',
      country: 'USA',
    },
  };

  // Object structure validation
  expect(userData).toHaveProperty('name');
  expect(userData).toHaveProperty('address.city');
  expect(userData.hobbies).toHaveLength(2);

  // Value validation
  expect(userData.name).toBeDefined();
  expect(userData.email).toContain('@');
  expect(userData.age).toBeGreaterThan(0);
  expect(userData.hobbies).toContain('reading');
}

Configuration Testing

JavaScript 
export default function () {
  const config = {
    apiUrl: __ENV.API_URL || 'https://api.example.com',
    timeout: parseInt(__ENV.TIMEOUT || '5000'),
    retries: parseInt(__ENV.RETRIES || '3'),
    features: (__ENV.FEATURES || 'feature1,feature2').split(','),
  };

  // Configuration validation
  expect(config.apiUrl).toContain('http');
  expect(config.timeout).toBeGreaterThan(0);
  expect(config.retries).toBeGreaterThanOrEqual(0);
  expect(config.features).toContain('feature1');
  expect(config.features).toHaveLength(2);
}

Error Handling Patterns

Graceful Error Handling

JavaScript 
export default function () {
  const response = http.get('https://quickpizza.grafana.com/');

  // Check response status first
  if (response.status === 200) {
    expect(response.body).toBeDefined();
    expect(response.body).toBeTruthy();
    expect(response.body).toContain('Pizza');
  } else {
    // Handle error response
    expect(response.status).toBeGreaterThanOrEqual(400);
    expect(response.body).toContain('error');
  }
}