THE COMPLETE GUIDE FOR SOFTWARE

INTEGRATION TESTING

DAVID TZEMACHWWW.MACHTESTED.COM

MAY 12 2017

AGENDA• WHAT IS INTEGRATION TESTING?

• THE INTEGRATION TESTING PROCESS

• WHEN SHOULD WE START INTEGRATION TESTS?

• WHY SHOULD WE USE INTEGRATION TESTS?

• INTEGRATION TESTS TECHNIQUES

• ENTRY AND EXIT CRITERIA

• BEST PRACTICES

WHAT IS INTEGRATION TESTING?

OVERVIEWINTEGRATION TESTING IS A TESTING APPROACH THAT WE USE TO TEST THE INTEGRATION AMONG TWO OR MORE

OBJECTS THAT SHOULD WORK AND INTERACT TOGETHER. DURING THE SOFTWARE DEVELOPMENT LIFE CYCLE, WE

WILL SEE THAT INTEGRATION TESTS ARE DONE ON DIFFERENT OBJECTS THAT ARE NOT DIRECTLY RELATED TO THE

SYSTEM COMPONENTS.

EXAMPLES:

• INTEGRATION TESTS AMONG THE SYSTEM MODULES (TESTING THE INTERFACE AND COMMUNICATION

AMONG MODULES).

• SYSTEM INTEGRATION TESTING (INTERFACES WITH EXTERNAL ORGANIZATIONS, INTEGRATION OF SYSTEM

PACKAGES, ETC.).

• INTEGRATION TESTS BETWEEN SYSTEMS AND OS.

INTEGRATION TESTING PROCESS

THE SEVEN PHASES OF INTEGRATION TESTING THERE IS A BASIC PROCESS THAT YOU CAN USE IN AN INTEGRATION TESTING PROJECT, THE PROCESS CONTAINS A FEW BASIC

PHASES THAT ARE RELEVANT TO ALMOST ANY OTHER TESTING PROJECT.

1. ANALYZE THE REQUIREMENTS AND SPECIFICATION OF EACH MODULE.

2. MAKE SURE THAT THE PERSON/TEAM THAT RUN THE TESTS ARE FAMILIAR WITH THE TECHNICAL DETAILS OF EACH MODULE

AND THE OVERALL SYSTEM ARCHITECTURE.

3. NOW THAT YOU ACQUIRE THE TECHNICAL DATA, REVIEW THE RISKS AND DETERMINE THE APPROACH TO REMOVE THEM.

4. DETERMINE THE TESTING STRATEGY WITH A CORRESPONDING TEST PLAN (TEST SCENARIOS, TEST CASES, EXPECTED

RESULTS, TEST PRIORITIES ETC.).

5. TEST EXECUTION (EXECUTING THE TESTS AND OPEN THE RELEVANT DEFECTS).

6. REVIEW OF THE TEST EXECUTION RESULTS AND RE-TEST IF NECESSARY.

7. REVIEW AND APPROVAL OF THE TESTING PHASE BEFORE PRECEDING TO THE NEXT TESTING LEVEL (SYSTEM TESTS).

WHEN TO START INTEGRATION TESTING?

IT’S TIME TO INTEGRATE!

INTEGRATION TESTING CAN BE PERFORMED ONCE WE HAVE COMPLETED AT LEASE TWO

COMPONENTS THAT WE CAN USE THROUGHOUT THE INTEGRATION TESTS.

[UNIT TESTING] -> [COMPONENT TESTING] -> [INTEGRATION TESTING] -> [SYSTEM TESTING]

WHY DO WE NEED TO USE INTEGRATION TESTS?

SO WHY DO WE NEED TO RUN INTEGRATION TESTS..?

THERE ARE MANY REASONS THAT CAN EXPLAIN THE NEED FOR THIS TYPE OF TESTS, LET’S EXAMINE

THREE OF THEM:

• ALTHOUGH EACH COMPONENT IS TESTED AND APPROVED (PRIOR TO THE INTEGRATION PHASE), THERE IS ALWAYS A CHANCE THAT THE INTERFACE THAT ALLOWING THE COMMUNICATION

BETWEEN THE MODULES CONTAIN DEFECTS THAT MAY TRIGGER FURTHER DEFECTS IN THE

INTEGRATED MODULES.

• INTEGRATION TESTS CAN LEAD TO MANY SITUATIONS THAT CAN TRIGGER DEFECTS THAT WILL

APPEAR ONLY IN SPECIFIC SITUATIONS SUCH AS CONFLICTS AND DEPENDENCIES BETWEEN TWO

MODULES.

EXAMINE THE BASIC SCENARIO

MODULE A SHOULD BE INTEGRATED WITH MODULE B, BOTH MODULES ARE TESTED AND READY TO INTERACT ONE

WITH EACH OTHER, NOW LET’S ASSUME THAT THE INTERFACE THAT SHOULD PASS THAT OUTPUT FROM MODULE A INTO MODULE B HAS A DEFECT THAT DOES NOT ALLOW HIM TO ENCRYPT/DECRYPT THE DATA.

AS A RESULT, THE TWO MODULES WILL FAIL TO INTERACT AND SOMETIMES, MODULE B WILL RECEIVE A CORRUPTED

AND UNEXPECTED DATA THAT WILL LEAD TO A MASSIVE FAILURE

INTEGRATION TEST TECHNIQUES

THE BIG BANG TECHNIQUETHIS TECHNIQUE IS ACTUALLY VERY SIMPLE…. BEFORE PERFORMING THE TESTS, DEVELOPMENT

TEAM WILL INTEGRATE ALL COMPONENTS/MODULES AT ONCE (SIMULTANEOUSLY) AND THEN

TESTED AS ONE BIG SYSTEM, ONCE DONE, THE INTEGRATION TESTS WILL START FOR SPECIFIC

COMPONENTS/MODULES.

THE BIG BANG TECHNIQUE (PROS VS CONS)

Advantages DisadvantagesMake sense when you need to test small systems Consumes the integration testing time (the integration tests can start only when

whole system is tested)

All integrations are done before starting the

integration tests

This technique is not relevant to large and complex systems.

Very difficult to trace the root cause of failures (Interfaces are not isolated during

the tests)

Increases the chance to miss the small interfaces that need to be tested (All

are integrated and tested at the same time)

THE INCREMENTAL TESTING TECHNIQUE

IN THIS TESTING TECHNIQUE, THE TESTING IS DONE WHEN MODULES THAT ARE LOGICALLY RELATED ARE INTEGRATED

ONE BY ONE AND TESTED, THIS APPROACH WILL CONTINUE UNTIL THE LAST MODULE IS INTEGRATED AND TESTED.

TO USE THIS TEST TECHNIQUE, WE WILL NEED TO USE STUBS AND DRIVERS THAT WILL HELP US TO RUN THE TESTS

WITHOUT THE NEED TO IMPLEMENT THE ENTIRE MODULE (SIMULATE THE COMMUNICATION AND DATA TRANSFERRING

BETWEEN THE MODULES).

WHEN USING THE INCREMENTAL APPROACH, WE CAN USE TWO DIFFERENT METHODS CALLED “TOP-DOWN” AND

“BOTTOM-UP”.

TOP-DOWN INTEGRATION TESTINGIN THIS TESTING TECHNIQUE, THE TESTING IS DONE WHEN MODULES THAT ARE LOGICALLY RELATED ARE INTEGRATED ONE BY ONE

AND TESTED, THIS APPROACH WILL CONTINUE UNTIL THE LAST MODULE IS INTEGRATED AND TESTED.

DUE TO THE NATURE OF THIS TECHNIQUE, WE WILL ALWAYS HAVE A TOP MODULE THAT CAN INTERACT WITH A LOWER MODULE, THE PROBLEM BEGINS WHEN THE LOWER MODULE IS STILL NOT DEVELOPED OR JUST NOT READY FOR INTEGRATION, AS A RESULT WE

CANNOT RUN THE TESTS WHICH AFFECT THE PROJECT TIMELINES.

TO OVERCOME THIS PROBLEM AND REDUCE THE WASTE OF TIME WHILE WAITING TO THE READINESS OF THE LOWER MODULE, WE

WILL USE “STUBS”, STUB IS A TERM THAT REPRESENTS A CODE SNIPPET THAT CAN BE USED TO ACCEPT THE REQUEST FROM THE TOP

MODULE AND RETURN A RESULT SIMILAR TO A REAL MODULE.

TOP-DOWN INTEGRATION TESTING(PROS VS CONS)

Advantages DisadvantagesIt’s easier to find the Root cause of defects (A Single integration

tested each time)

Although stubs are similar to the real module, we will still need to make

further tests once the module is ready, which consume more time.

This approach will allow the team to rank the major flows first, as

a result, the most important defects will be found and removed

before other defects that are less important.

In complex systems that built with many modules, we will need to develop

multiple stubs

Comparing to the “Big-bang” approach, we can save time

we do not need to wait for all modules to be developed

In real world testing scenarios that involve complex design logic, you may

have trouble to predicting how the stubs will react during the tests.

often, you will find that the development of stubs will cost more than the

actual module development

BOTTOM-UP INTEGRATION TESTING

IN THIS TECHNIQUE, WE WILL START THE TESTS FROM THE LOWEST MODULE OF THE APPLICATION AND GRADUALLY PROGRESSES

TOWARDS THE TOP MODULES OF THE APPLICATION UNTIL ALL MODULES ARE INTEGRATED AND VALIDATED AS A WHOLE SYSTEM.

THE PROBLEM WITH THIS TECHNIQUE IS SIMILAR TO THE PROBLEM THAT WE HAD IN THE “TOP-DOWN” TECHNIQUE WHEN YOU

START TO TEST THE INTEGRATION BETWEEN TWO MODULES THAT ONE OF THEM IS STILL NOT READY TO BE INTEGRATED AND TESTED

(THE HIGHER MODULE IN OUR CASE).

TO OVERCOME THIS PROBLEM IN THE “TOP-DOWN” TECHNIQUE, WE USED “STUBS” THAT ARE NOT RELEVANT TO OUR APPROACH

WERE YOU NEED TO USE ANOTHER SIMULATOR CALLED “DRIVER” THAT WILL ALLOW YOU TO USE THE DRIVER TO TRIGGER/CALL THE

FUNCTIONS FROM THE LOWEST MODULE AND TO SIMULATE THE TEST INPUTS TO THE TESTED MODULE.

BOTTOM-UP INTEGRATION TESTING(PROS VS CONS)

Advantages DisadvantagesDefects that are found in the lowest modules are easier to detect

The whole system is not built until the creation of the last Top module

It’s easier to find the Root cause of defects (A Single integration is tested each time)

The critical design flows are tested at the end which, increases the risk to find critical defects in this flow

Comparing to the “Big-bang” approach, we can save time because we do not need to wait for all modules to be developed

ENTRY AND EXIT CRITERIA FOR INTEGRATION

TESTING

ENTRY CRITERIA FOR INTEGRATION TESTING • THERE IS A TECHNICAL DOCUMENT THAT DESCRIBES THE EXPECTED BEHAVIOR OF EACH INTERFACE.

• ALL MAJOR/CRITICAL DEFECTS FROM THE EARLY TESTING PHASES ARE CLOSED AND VERIFIED.

• THE TEST ENVIRONMENT IS READY TO SUPPORT THE TEST SCENARIOS.

• THE MODULES ARE INTEGRATED TOGETHER AND READY FOR TESTING.

• THERE IS A DOCUMENT THAT CONTAINS THE TEST STRATEGY.

• EACH COMPONENT IS TESTED AND APPROVED.

• EACH COMPONENT HAS A LIST OF UNIT TESTS.

• ALL RISKS ARE ANALYZED AND REMOVED.

• ALL MODULES ARE IDENTIFIED.

EXIT CRITERIA FOR INTEGRATION TESTING

• ALL TEST CASES FROM THE TEST PLAN ARE EXECUTED AND APPROVED.

• ALL MAJOR/CRITICAL BUGS ARE RE-TESTED, FIXED AND VERIFIED.

• THE TEST PLAN IS SIGNED –OFF.

• A TEST REVIEW IS DONE.

BEST PRACTICESFOR INTEGRATION TESTING

HOW CAN WE ACHIEVE MORE FROM OUR TESTS? • IN ANY CASE THAT IT’S POSSIBLE, AUTOMATE YOUR TESTS, OTHERWISE, YOU

WILL RUN EACH TEST MANUALLY PER THE INTEGRATION OF EACH MODULE.

• MAKE SURE THAT YOU FAMILIAR WITH THE MODULES TO BE INTEGRATED

(ESPECIALLY THE DESIGN AND ARCHITECTURE OF THE MODULES).

• DETERMINE THE INTEGRATION TEST STRATEGY, THIS STRATEGY SHOULD ALLOW

YOU ACCOMPLISH THE TESTING GOALS.

• MAKE SURE THAT EACH COMPONENT IS TESTED AND APPROVED BEFORE

EXECUTING THE INTEGRATION TESTS.

• MAKE SURE THAT YOU HAVE A DETAILED TECHNICAL DOCUMENT THAT

EXPLAINS HOW THE INTERACTIONS BETWEEN EACH TWO MODULES

(INTERFACES AND HOW THEY SHOULD WORK).

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