4 - blackbox testing

8/12/2019 4 - BlackBox Testing

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Black

BoxTesting


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?


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...a software testing techniquesin which

functionality of the software under test (SUT)

is tested without looking at the internal code structure,

implementation details andknowledge of internal paths of the software.

Black box testing is...

This type of testing is based entirely on

the software requirements and specifications.


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...on inputs and output

of the software systemwithout bothering about

internal knowledge

of the software program

FOCUS


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STEPSInitially requirements and specifications

of the system are examined

Tester chooses valid inputs (positive test scenario),

also some invalid inputs (negative test scenario)

Tester determines expected outputsfor all those inputs

Software tester constructs test cases

with the selected inputs

The test cases are executed

Software tester compares the actual outputs

with the expected outputs

Defects if any are fixed and re-tested


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TYPES...

Functional Testing

Black Box Testing

Non-Functional

Testing


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Test Case


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...a set of test inputs, execution conditions, and expected results

developed for a particular objective,

such as to exercisea particular program path or

to verifycompliance with a specific requirement

Test caseis...


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CASETESTUSE

from


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Actors and Use cases

in an ATM Machine

This Use Case begins with the ATM in the Ready State.

1. Initiate Withdraw - Customer inserts bank card in the card reader on the ATM machine

2. Verify Bank Card - T he ATM reads the account code from the magnetic st rip on the bank card and checks if it is anacceptable bank card.

3. Enter PIN - The ATM asks for the c ustomer's PIN code (4 digits)

4. Verify account code and PIN - The account code and PIN are verified to determine if the account is valid and if the PIN

entered is the correct PIN for the account. For this flow, the account is a valid account and the PIN is the correct PIN

associated with this account.

5. ATM Options - The ATM displays the different alternatives available at this ATM. In this flow, the bank customer always

selects "Cash Withdraw."

6. Enter Amount - The ATM the amount to withdraw. For this flow the customer selects a pre-set amount ($10, $20, $50,or $100).

7. Authorization - The ATM initiates the verification process with the Banking System by sending the Card ID, PIN, Amount,

and Account information as a transaction. For this flow, the Banking System is online and replies with the authorization to

complete the cash withdrawal successfully and updates the account balance accordingly.

8. Dispense - The Money is dispensed.

9. Return Card - The Bank Card is returned.

10. Receipt - The receipt is printed and dispensed. The ATM also updates the internal log accordingly.

Use Case ends with the ATM in the Ready State.

Basic Flow


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Alternate Flow 1 - Not a

valid Card

In Basic Flow Step 2 - Verify Bank Card, if the card is not valid, it is ejected with an appropriate message.

Alternate Flow 2 - ATM

out of Money

At Basic Flow Step 5 - ATM Options, if the ATM is out of money, the "Cash Withdraw" option will not be available.

Alternate Flow 3 -

Insufficient funds in ATM

At Basic Flow Step 6 - Enter Amount, if the ATM contains insufficient funds to dispense the requested amount, an

appropriate message will be displayed, and rejoins the basic flow at Step 6 - Enter Amount.

At Basic Flow Step 4 - Verify Account and PIN, the customer has three tries to enter the correct PIN.

If an incorrect PIN is entered, the ATM displays the appropriate message and if there are still tries remaining, this flow

rejoins Basic Flow at Step 3 - Enter PIN.

If, on the final try the entered PIN number is incorrect, the card is retained, ATM returns to Ready State, and this use case

terminates.

Alternate Flow 5 - No

Account

At Basic Flow Step 4 - Verify Account and PIN, if the Banking system returns a code indicating the account could not be

found or is not an account which allows withdrawals, the ATM displays the appropriate message and rejoins the Basic Flow

at Step 9 - Return Card.

Alternate Flow 6 -

Insufficient Funds in

Account

At Basic Flow Step 7 - Authorization, the Banking system returns a code indicat ing the account balance is less than the

amount entered in Basic Flow Step 6 - Enter Amount, the ATM displays the appropriate message and rejoins the Basic F low

at Step 6 - Enter Amount.

Alternate Flow 7 - Daily

maximum withdrawal

amount reached

At Basic Flow Step 6 - Authorization, the Banking system returns a code indicating that, including this request for

withdrawal, the customer has or will have exceeded the maximum amount allowed in a 24 hour period, the ATM displays the

appropriate message and rejoins the Basic F low at Step 6 - Enter Amount.

Alternate Flow 4 -Incorrect PIN

Alternate Flow...


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CW1. Scenario 1 - Successful Cash Withdraw V V V V V Successful cash withdrawal.

CW2. Scenario 2 - ATM out of Money V V V V I Cash Withdraw option

unavailable, end of use caseCW3. Scenario 3 - Insufficient funds in ATM V V V V I Warning message, return to

Basic Flow Step 6 - Enter

Amount

V Warning message, return to

Basic Flow Step 4, Enter P IN

CW6. Scenario 4 - Incorrect PIN (= 0 tries left) I V n/a V V Warning message, card

retained, end of use case

CW5. Scenario 4 - Incorrect PIN (= 1 try left) I V n/a V

Expected Result

CW4. Scenario 4 - Incorrect PIN (> 1 left) I V n/a V V Warning message, return to

Basic Flow Step 4, Enter P IN

Amount Entered

(or chosen)TC ID# Scenario / Condition PIN Account #

Amount in

AccountAmount in ATM

CW1. Scenario 1 - Successful Cash Withdraw 4987 809 - 498 50 500 2,000 Successful cash withdrawal. Account

balance updated to 450.00

CW2. Scenario 2 - ATM out of Money 4987 809 - 498 100 500 0 Cash Withdraw option unavailable,

end of use case

CW3. Scenario 3 - Insufficient funds in ATM 4987 809 - 498 100 500 70 Warning message, return to Basic

Flow Step 6 - Enter Amount

2,000 Warning message, return to Basic

Flow Step 4, Enter PIN

CW6. Scenario 4 - Incorrect PIN (= 0 tries left) 4978 809 - 498 n/a 500 2,000 Warning message, card retained,end of use case

CW5. Scenario 4 - Incorrect PIN (= 1 try left) 4978 809 - 498 n/a 500

Expected Result

CW4. Scenario 4 - Incorrect PIN (> 1 left) 4978 809 - 498 n/a 500 2,000 Warning message, return to Basic

Flow Step 4, Enter PIN

Amount

Entered

(or chosen)

TC

ID#Scenario / Condition PIN

Account

#

Amount in

Account

Amount in

ATM

Matrix Data Element

Actual Data Values


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Strategi pengujian yang hanya fokus kepada

faktor fungsionalitas dan spesifikasi perangkat

lunak.

Testing dilakukan bukan pada awal proses

pengujian, tapi pada beberapa tahap

berikutnya

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Pengujian dirancang untuk menjawab beberapa

pertanyaan sebagai berikut:1. Bagaimana validitas fungsionalnya diuji?

2. Bagaimana perilaku sistem dan performansi diuji?

3. Jenis inputseperti apa yang akan menghasilkan kasus uji yang baik ?

4. Apakah sistem secara khusus sensitif terhadap nilai inputtertentu ?

5. Bagaimana batasan-batasan kelas data diisolasi?

6. Berapa rasio data dan jumlah data yang dapat ditoleransi oleh sistem?

7. Apa akibat yang akan timbul dari kombinasi spesifik data pada operasi

sistem?

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Menganalisis kebutuhan dan spesifikasi dari

perangkat lunak.

Pemilihan jenis inputyang memungkinkan

menghasilkan outputbenar serta jenis input

yang memungkinkan outputsalah pada

perangkat lunak yang sedang diuji.

Menentukan outputuntuk suatu jenis input.

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Pengujian dilakukan dengan input-inputyang

telah benar-benar diseleksi.

Melakukan pengujian.

Pembandingan outputyang dihasilkan dengan

outputyang diharapkan.

Menentukan fungsionalitas yang seharusnyaada pada perangkat lunak yang sedang diuji.

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Black Box Testing dapat dilakukan pada setiap

level pembangunan sistem

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Keunggulan

Dapat memilih subset testyang secara efektif dan

efisien dapat menemukan cacat.

Dapat membantu memaksimalkan testing

investment.

Kelemahan

Terdapat kemungkinan masih ada beberapa jalureksekusi yang belum pernah diuji oleh tester

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Equivalence Class Testing

Teknik yang digunakan untuk mengurangi jumlah test caseyang ada pada saat pengujian. Kebanyakan testermenggunakan teknik yang simpel ini meskipun secaraformal tester tersebut tidak mengetahui mengenai metodedesain formal dalam pengujian perangkat lunak.

Kasus uji yang didesain untuk Equivalence class testingberdasarkan pada evaluasi dari ekuivalensi jenis/class untukkondisi input.

Class-class yang ekuivalen merepresentasikan sekumpulankeadaan valid dan invalid untuk kondisi input. Biasanyakondisi input dapat berupa spesifikasi nilai numerik, kisarannilai, kumpulan nilai yang berhubungan atau kondisiboolean.


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Langkah-langkah

Equivalence Class Testing

Identifikasi kelas-kelas yang ekuivalen

(equivalence class).

Buat test caseuntuk tiap-tiap equivalence class.

Jika memungkinkan buat test case tambahan yangacak yang memungkinkan ditemukannya cacat

pada perangkat lunak.


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Continuous

equivalence classesContoh nilai untuk pendapatan/ salaryyang disyaratkan

untuk melakukan pembelian rumah secara kredit:


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Discrete

equivalence classes

Contoh nilai untuk jumlah kemilikan rumah yang disyaratkan



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Single selection

equivalence classes

Contoh nilai untuk kategori pengajuan yang disyaratkan



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Multiple selection

equivalence classContoh nilai untuk jenis rumah yang disyaratkan untuk

melakukan pembelian rumah secara kredit:


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Boundary Value Testing

Boundary value testing fokus kepada suatu

batasan nilai dimana kemungkinan terdapat cacat

yang tersembunyi.

BVT mengarahkan pada pemilihan kasus uji yangmelatih nilai-nilai batas. BVT merupakan desain

teknik kasus uji yang melengkapi Equivalence

class testing. Dari pada memfokuskan hanya padakondisi input, BVA juga menghasilkan kasus uji

dari domain output.


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Langkah-langkah

Boundary Value Testing

Identifikasi kelas-kelas yang ekuivalen

(equivalence class).

Identifikasi batasan untuk tiap equivalence class.

Buat test case untuk tiap batasan suatu nilaidengan memilih titik pada batasan, satu titik pada

nilai bawah batasan dan satu titik pada nilai atas

batasan.


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Boundary values for a continuous

range of inputs

Tes data input untuk batas bawah adalah {$999, $1,000, $1,001} dan

untuk batas atas {$83,332, $83,333, $83,334}.

Contoh untuk nilai pendapatan/ salary:


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Boundary values for a discrete range

of inputs.

Tes data input untuk batas bawah adalah {0, 1, 2} dan untuk batas atas {4,

5, 6}.

Contoh nilai untuk jumlah tempat tinggal (dwellings) yang dimiliki olehseseorang:


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Contoh Kombinasi Pengujian

Sangat penting untuk menginputkan nilai

kombinasi secara besamaan, misalkan:

4 - blackbox testing

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