@qavajs/validation

A validation library for test automation that provides two interfaces:

• Natural language transformer — converts human-readable sentences like "should deeply equal" into executable validation functions, designed for BDD/Cucumber steps
• Standalone expect() API — a chainable, extensible assertion library with built-in matchers, negation, soft assertions, and polling

Installation

npm install @qavajs/validation

Natural Language Validation

getValidation(description, options?)

Parses a plain English validation description and returns a (received, expected) => void function.

import { getValidation } from '@qavajs/validation';

const validate = getValidation('to equal');
validate(1, 1);   // passes
validate(1, 2);   // throws AssertionError: [AssertionError] expected 1 to equal 2

// Negation
const notEqual = getValidation('not to equal');
notEqual(1, 2);   // passes

// Soft assertion (throws SoftAssertionError instead of AssertionError)
const softValidate = getValidation('to equal', { soft: true });

Accepted phrase patterns

[is|do|does|to] [not|to not] [to] [be] [softly] <validation>

Examples: "equal", "is equal", "does not equal", "to softly contain", "is not deeply equal"

getPollValidation(description, options?)

Like getValidation, but returns an async function that retries until the assertion passes or the timeout is exceeded.

import { getPollValidation } from '@qavajs/validation';

const pollEqual = getPollValidation('to equal');

// received must be a function returning a value or Promise
await pollEqual(() => fetchStatus(), 'ready', { timeout: 5000, interval: 500 });

poll(fn, options?)

Generic polling helper — retries fn until it resolves without throwing.

import { poll } from '@qavajs/validation';

await poll(async () => {
    const status = await getStatus();
    if (status !== 'ready') throw new Error('Not ready yet');
}, { timeout: 10000, interval: 500 });

validationRegexp

A RegExp that matches any supported validation phrase within a larger string. Useful for building Cucumber step definitions.

import { validationRegexp } from '@qavajs/validation';

// Example step pattern:
// /^value {validationRegexp} {string}$/

---

Standalone expect() API

import { expect } from '@qavajs/validation';

Equality & Comparison

Matcher	Description
.toSimpleEqual(expected)	Non-strict equality (==)
.toEqual(expected)	Strict equality using Object.is
.toBe(expected)	Strict equality using Object.is
.toStrictEqual(expected)	Strict equality (===)
.toDeepEqual(expected)	Deep equality, array order-insensitive
.toDeepStrictEqual(expected)	Deep equality via util.isDeepStrictEqual, order-sensitive
.toCaseInsensitiveEqual(expected)	Lowercased string comparison
.toBeGreaterThan(expected)	received > expected
.toBeGreaterThanOrEqual(expected)	received >= expected
.toBeLessThan(expected)	received < expected
.toBeLessThanOrEqual(expected)	received <= expected

Containment & Membership

Matcher	Description
.toContain(expected)	String includes substring, or array includes element
.toMatch(expected)	String matches RegExp or includes substring
.toHaveMembers(expected)	Array has exactly the same members (order-insensitive)
.toIncludeMembers(expected)	Array is a superset of expected members
.toHaveProperty(key, value?)	Object has property; optionally checks value
.toHaveLength(expected)	Array or string has given length

Type Checks

Matcher	Description
.toHaveType(expected)	typeof received === expected; also accepts 'array'
.toBeNull()	received === null
.toBeUndefined()	received === undefined
.toBeNaN()	Number.isNaN(received)
.toBeTruthy()	!!received

Schema & Predicate

Matcher	Description
.toMatchSchema(schema)	Validates against a JSON Schema using ajv
.toSatisfy(fn)	Passes if fn(received) returns true

Functions & Promises

Matcher	Description
.toThrow(expected?)	Function throws; optionally matches error message
.toPass()	Async function resolves without throwing
.toResolveWith(expected)	Promise resolves with expected value
.toRejectWith(expected)	Promise rejects with a message containing expected string

Negation — .not

Negate any matcher with .not:

expect(2).not.toEqual(1);
expect('hello').not.toContain('xyz');
expect([1, 2]).not.toHaveMembers([3, 4]);

Soft Assertions — .soft

Soft assertions throw SoftAssertionError instead of AssertionError. Useful when you want to distinguish blocking vs non-blocking failures.

expect(value).soft.toEqual(expected);
expect(value).soft.not.toContain('bad');

Polling — .poll(options?)

Wrap a function with .poll() to retry the assertion until it passes or times out. The received value must be a function.

// Retries every 100ms for up to 5 seconds (defaults)
await expect(() => getValue()).poll().toEqual('ready');

// Custom timeout and interval
await expect(() => fetchStatus()).poll({ timeout: 10000, interval: 500 }).toEqual('done');

.configure(options)

Apply multiple options at once. Useful for dynamically building assertions.

expect(value).configure({
    not: true,       // negate
    soft: true,      // use SoftAssertionError
    poll: true,      // enable polling
    timeout: 5000,   // poll timeout in ms
    interval: 100    // poll interval in ms
});

---

Custom Matchers

Extend expect with your own matchers using .extend(). Each matcher is a function with this typed as MatcherContext and must return { pass: boolean, message: string }.

import { expect } from '@qavajs/validation';

const customExpect = expect.extend({
    toBeEven(this, expected) {
        const pass = this.received % 2 === 0;
        const message = this.formatMessage(this.received, expected, 'to be even', this.isNot);
        return { pass, message };
    }
});

customExpect(4).toBeEven();
customExpect(3).not.toBeEven();

All built-in modifiers (.not, .soft, .poll) work automatically with custom matchers.

---

Error Types

Class	Extends	When thrown
AssertionError	Node.js AssertionError	Standard assertion failure
SoftAssertionError	AssertionError	Soft assertion failure (.soft)

Error messages follow the format:

[AssertionError] expected 1 not to equal 1
[SoftAssertionError] expected 'hello' to contain 'xyz'

---

Supported Natural Language Validations

All keywords can be combined with negation (not, does not, is not, to not) and the softly modifier.

Keyword	Equivalent matcher
equal	.toSimpleEqual() (non-strict ==)
strictly equal	.toEqual() (Object.is)
deeply equal	.toDeepEqual() (order-insensitive)
deeply strictly equal	.toDeepStrictEqual() (util.isDeepStrictEqual)
case insensitive equal	.toCaseInsensitiveEqual()
contain	.toContain()
match	.toMatch()
have member	.toHaveMembers()
include member	.toIncludeMembers()
have property	.toHaveProperty()
above / greater than	.toBeGreaterThan()
below / less than	.toBeLessThan()
have type	.toHaveType()
match schema	.toMatchSchema()
satisfy	.toSatisfy()

---

Running Tests

npm test

---

License

MIT