computer science

System integration testing

System integration testing is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand System integration testing rather than just read about it. In short: System integration testing (SIT) involves the overall testing of a complete system of many subsystem components or elements. The system under test may be composed of electromechanical or computer hardware, or software, or hardware with embedded software, or hardware/software with human-in-the-loop testing.

Key takeaways

System integration testing belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect System integration testing to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of System integration testing from memory before moving on to harder problems.

Reference excerpt

System integration testing (SIT) involves the overall testing of a complete system of many subsystem components or elements. The system under test may be composed of electromechanical or computer hardware, or software, or hardware with embedded software, or hardware/software with human-in-the-loop testing. SIT is typically performed on a larger integrated system of components and subassemblies that have previously undergone subsystem testing. SIT consists, initially, of the "process of assembling the constituent parts of a system in a logical, cost-effective way, comprehensively checking system execution (all nominal and exceptional paths), and including a full functional check-out." Following integration, system test is a process of "verifying that the system meets its requirements, and validating that the system performs in accordance with the customer or user expectations." In technology product development, the beginning of system integration testing is often the first time that an entire system has been assembled such that it can be tested as a whole. In order to make system testing most productive, the many constituent assemblies and subsystems will have typically gone through a subsystem test and successfully verified that each subsystem meets its requirements at the subsystem interface level. In the context of software systems and software engineering, system integration testing is a testing process that exercises a software system's coexistence with others. With multiple integrated systems, assuming that each have already passed system testing, SIT proceeds to test their required interactions. Following this, the deliverables are passed on to acceptance testing.

Software system integration testing For software SIT is part of the software testing life cycle for collaborative projects. Usually, a round of SIT precedes the user acceptance test (UAT) round. Software providers usually run a pre-SIT round of tests before consumers run their SIT test cases. For example, if an integrator (company) is providing an enhancement to a customer's existing solution, then they integrate the new application layer and the new database layer with the customer's existing application and database layers. After the integration is complete, users use both the new part (extended part) and old part (pre-existing part) of the integrated application to update data. A process should exist to exchange data imports and exports between the two data layers. This data exchange process should keep both systems up-to-date. The purpose of system integration testing is to ensure all parts of these systems successfully co-exist and exchange data where necessary. There may be more parties in the integration, for example the primary customer (consumer) can have their own customers; there may be also multiple providers.

See also Integration testing User acceptance testing (UAT) Systems integration

References

Worked examples

Example 1 — a first encounter with System integration testing

Start with the simplest possible case. Write down what System integration testing claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to System integration testing before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about System integration testing ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of System integration testing

In research: System integration testing appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses System integration testing in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: System integration testing is common in secondary-school and first-year university syllabi. It links to neighbouring topics Software testing, System integration, Systems engineering, so understanding it makes those chapters shorter.
In everyday life: Look for System integration testing outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study System integration testing in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what System integration testing means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain System integration testing out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is System integration testing in simple terms?

Why does System integration testing matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study System integration testing?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on System integration testing.