Assertions and tests

The test section of a step asserts the response. Plain values are compared for equality, and the body is matched key by key, as deep as you write it:

test:
  status: 400
  body:
    error:
      code: DIVISION_BY_ZERO

JavaScript expressions

For anything beyond equality, prefix the value with $expr: and write JavaScript, where value is the actual value being tested:

test:
  body:
    count: "$expr: value > 10"
    items: "$expr: Array.isArray(value) && value.length >= 3"
    user:
      age: "$expr: value >= 18 && value <= 65"

Validation	Expression
Greater than	$expr: value > 0
Exact value	$expr: value === 2
In a range	$expr: value >= 5 && value <= 10
String contains	$expr: typeof value === 'string' && value.includes('ok')
Array has items	$expr: Array.isArray(value) && value.length > 0
Property exists	$expr: typeof value === 'object' && 'id' in value
Date after	$expr: new Date(value) > new Date('2023-01-01')

Cover the unhappy paths too: asserting that a missing resource returns 404 is what catches the regression that starts answering 200.