Assertion Operators

A complete catalog of all operators available for response validation in Plyson.

Plyson provides a wide range of operators to validate API responses. These operators are powered by Playwright's expect library and can be used against both response bodies and headers.

Equality & Existence

Operator	Value	Description
`equals`	Any	Checks if the actual value is equal to the expected value.
`notEquals`	Any	Checks if the actual value is NOT equal to the expected value.
`equalsIgnoreCase`	String	Case-insensitive string equality check.
`exists`	(None)	Checks if the value is defined (not `undefined`).
`notExists`	(None)	Checks if the value is `undefined`.
`isNull`	(None)	Checks if the value is explicitly `null`.
`isNotNull`	(None)	Checks if the value is NOT `null`.

Numeric Comparisons

Operator	Value	Description
`isGreaterThan`	Number	`Actual > Value`
`isLessThan`	Number	`Actual < Value`
`isGreaterThanOrEquals`	Number	`Actual >= Value`
`isLessThanOrEquals`	Number	`Actual <= Value`

Strings & Arrays

Operator	Value	Description
`contains`	String	Checks if a string contains a substring.
`notContains`	String	Checks if a string does NOT contain a substring.
`matches`	String (Regex)	Validates a string against a Regular Expression.
`hasLength`	Number	Checks if a string or array has an exact length.
`hasMinLength`	Number	Checks for minimum length.
`hasMaxLength`	Number	Checks for maximum length.
`includes`	Any	Checks if an array contains a specific item.
`notIncludes`	Any	Checks if an array does NOT contain an item.
`isEmpty`	(None)	Checks if a string or array is empty.
`isNotEmpty`	(None)	Checks if a string or array is NOT empty.

Advanced Validation

`containsSubset`

Checks if the response object contains the specified properties and values. This is great for partial object matches.

{
  "operator": "containsSubset",
  "value": { "role": "ADMIN", "active": true }
}

`notContainsSubset`

Ensures that the response object does NOT match the provided subset of properties.

Type Checks

Validate the data type of the response field:

isString
isNumber
isBoolean
isArray
isObject

Complete Example

{
  "title": "Validate User Details",
  "from": "body",
  "path": "$.user",
  "operator": "containsSubset",
  "value": {
    "email": "jane@example.com",
    "settings": { "theme": "dark" }
  }
}

Assertion Operators

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