Basic Assertions - dylanparry/ceylon GitHub Wiki

1. toExist
2. toNotExist
3. toBe
4. toNotBe
5. toEqual
6. toNotEqual
7. toBeA
8. toNotBeA

expect(item: any).toExist(message?: string): this;

Asserts that the tested item is not one of the following:

• undefined
• null
• '' (empty string)
• [] (empty array)
• {} (empty object)

Outputs an optional message in case of a failed assertion.

Unlike some other assertion libraries, this will not throw an Assertion Error for:

• 0
• false
• NaN

As all these are considered to be existant values.

expect('I am a string').toExist();

expect('').toExist(); // Assertion Error

expect(item: any).toNotExist(message?: string): this;

Asserts that the tested item is one of the following:

• undefined
• null
• '' (empty string)
• [] (empty array)
• {} (empty object)

Outputs an optional message in case of a failed assertion.

Unlike some other assertion libraries, this will throw an Assertion Error for:

• 0
• false
• NaN

As all these are considered to be existant values.

expect('').toNotExist();

expect(false).toNotExist(); // Assertion Error

expect(item: T).toBe(value: T, message?: string): this;

Asserts that the tested item is strictly equal to value.

Outputs an optional message in case of a failed assertion.

expect(50 + 50).toBe(100);

expect('I am a string').toBe('I AM A STRING'); // Assertion Error

expect(item: T).toNotBe(value: T, message?: string): this;

Asserts that the tested item is not strictly equal to value.

Outputs an optional message in case of a failed assertion.

expect('I am a string').toNotBe('I AM A STRING');

expect(50 + 50).toNotBe(100); // Assertion Error

expect(item: T).toEqual(value: T, message?: string): this;

Asserts that the tested item is deep equal to value. This should be used for testing objects and arrays.

Outputs an optional message in case of a failed assertion.

expect({ id: 1, name: 'Example' }).toEqual({ id: 1, name: 'Example' });

expect({ id: 1, name: 'Example' }).toEqual({ id: 2, name: 'Example' }); // Assertion Error

expect(item: T).toNotEqual(value: T, message?: string): this;

Asserts that the tested item is not deep equal to value. This should be used for testing objects and arrays.

Outputs an optional message in case of a failed assertion.

expect({ id: 1, name: 'Example' }).toNotEqual({ id: 2, name: 'Example' });

expect({ id: 1, name: 'Example' }).toNotEqual({ id: 1, name: 'Example' }); // Assertion Error

expect(item: T).toBeA(constructor: string, message?: string): this;

Asserts that the type of the tested item is constructor.

Outputs an optional message in case of a failed assertion.

expect(100).toBeA('number');

expect('100').toBeA('number'); // Assertion Error

• toBeAn

expect(item: T).toNotBeA(constructor: string, message?: string): this;

Asserts that the type of the tested item is not constructor.

Outputs an optional message in case of a failed assertion.

expect('100').toNotBeA('number');

expect(100).toNotBeA('number'); // Assertion Error

• toNotBeAn