expect
Small assertion module.
Function | Description |
---|---|
expect(a ).toBe(b ) |
Asserts that a and b are the same (=== ). |
expect(a ).toBeInstanceOf(b ) |
Asserts that a is an instance of b
|
expect(a ).toEqual(b ) |
If b is a primitive then:a === b If b is not a primitive:• Asserts same prototype • Asserts same properties • Asserts property value recursively with toEqual
|
expect(a ).toHaveProperty(b ) |
Asserts that object a has an enumerable/non-enumerable property called b . |
expect(a ).toHaveSubString(b ) |
Asserts that string a contains the sub-string b . |
expect(fn ).toThrowError() |
Asserts that fn throws an error. |
expect(fn ).toThrowError(message ) |
Asserts that fn throws an error with a message containing message . |
All assertions (except toThrowError
) can be negated with .not
:
expect(1).not.toBe(2)
Example usage:
const {createExpectationsContext} = require("expect")
const {expect, end} = createExpectationsContext()
expect(1).toBe(1)
end()