Testing Layers

 /andreipfeiffer

 @pfeiffer_andrei

Andrei Pfeiffer

Timisoara / RO

// code designer

// organizer, speaker

manual
________

end to end
_________________

integration
___________________________

unit
_______________________________________

few / trivial
________

-
_________________

-
___________________________

many / technical
_______________________________________

the smallest part of the SUT
method or function

unit

what to test?

API

public interface

no privates

// module pattern

const module = (() => {

    // private declarations

    return {
        foo() {};
    };
})();

...

module.foo();

// ES6 modules

// private declarations
export function foo() {};

...

import * as module from "module.js";

module.foo();

privates are "private"

// interface contract

assertEqual(getText(0), "0 products");
assertEqual(getText(1), "1 product");
assertEqual(getText(2), "2 products");

// privates are details / inditect testing

function naivePlural(value) {
    return value + 's';
}

export function getText(nr) {
    let text = 'product';
    if (nr !== 1) {
        text = naivePlural(text);
    }
    return `${nr} ${text}`;
};

// refactoring changes details

function pluralize(value) {
    return value + 's';
}

export function getText(nr) {
    let text = 'product';
    if (nr !== 1) {
        text = pluralize(text);
    }
    return `${nr} ${text}`;
};

business logic

our own code, edge cases, bugs

no 3rd party libs, framework

// N-way binding

// some viewModel
vm.list = [1, 2, 3];

...

// some view
<ul {{foreach: item as vm.list}}>
    <li>{{item}}</li>
<ul>

// N-way binding

// rendered result
<ul>
    <li>1</li>
    <li>2</li>
    <li>3</li>
<ul>

// business logic

vm.list = [1, 2, 3];

// business logic

vm.getIndex = (nr) => {
    return nr - 1;
};

white box

isolate SUT

stub / mock

how to test?

SUT

dependency

dependency

xhr / http / database / disk

SUT

dependency

dependency

xhr / http / database / disk

SUT

dependency

foo()

fn()

do()

foo()

bar()

sociable tests

dependency

Flawed Code coverage

foo()

fn()

foo()

bar()

do()

SUT

Solitary tests

SUT

dependency

fn()

do()

foo()

bar()

mock('foo');

stub('foo');

communication between
different parts of the system

integration

component testing

aka.

components communication

database

requests

disk I/O

what to test?

white box

don't isolate / use real objects

no stubs/mocks

how to test?

test database

fixtures

tests use cases, from the user's seat

end 2 end

GUI / acceptance / system

aka.

test the application
not the code

what to test?

black box

mimic real events / requests

how to test?

setup entire app

non-automated tests

manual testing

user testing

aka.

what to test?

content

semantics

correctness

style

alignment

beautifulness

user friendliness

UX

speed

slowest
________

even slower
_________________

slower
___________________________

fast
_______________________________________

Finished in 0.62 secs

SUMMARY:
✔ 52 tests completed

unit speed

35 tests passing (3s)

integration speed

6 scenarios (6 passed)
Done in 21.7 secs

e2e speed

???
________

~300x slower
_________________

~10x slower
___________________________

unit test reference
_______________________________________

unit:
integration:
end 2 end:

0.62 secs
3.00 secs
21.70 secs

unit:
integration:
end 2 end:

62 secs
5.0 mins
36.1 mins

x 100

conclusions

e2e is ideal

slow

best integration

automated

cumbersome setup

deferred run

unit testing is handy

tests only isolated code

fast

automated

simple setup

continuous run / TDD

unit

e2e

automated

integration

speed

run frequency

setup

yes

yes

high

low

low

high

low

high

complex

simple

q&a

muito obrigado