What are Specification-Based Test Design Techniques?
Specification-based test design, told as a story about testing with a handful of representative cases picked from the rulebook, without reading the whole manuscript.
Checking every single case would take a lifetime.Just one age field has far too many possible values.
The number of values an age field could take is practically infinite.Trying every single value just isn't possible.
Spec-based test design picks representative cases from the rulebook alone.Without reading the whole manuscript, you test with just a few cases picked from the rules.
A handful of representative cases checks the rule's range and edges.One normal case, two out-of-range cases, and the values just either side of the boundary — that's often enough.
The rulebook alone doesn't catch every error.Rare combinations the rules never anticipated still need other methods, like exploratory testing, alongside this.
Specification-based test design = instead of reading the whole manuscript, picking a small set of representative cases straight from the written rules.
Specification-based (black-box) test design creates test cases from the requirements spec alone, without looking at the internal code. The main techniques are equivalence partitioning (testing one representative from each group of similar inputs), boundary value analysis (testing just either side of a boundary), decision table testing (laying out condition combinations in a table), and state transition testing (testing at each change of state).
When grown-ups say it
- Specification-Based Testing
- Testing based on the rulebook alone. Can be done without looking at the code — black-box.
- Equivalence Partitioning
- Grouping similar inputs together. Each group is assumed to behave alike, so one test stands for it.
- Boundary Value Analysis
- Checking just either side of the line. Mistakes often show up right at the boundary.
- Decision Table Testing
- Laying out condition combinations as a table. Keeps you from missing a combination when several conditions interact.
- State Transition Testing
- Testing every time the story moves to a new stage. Used for flows like booked → confirmed → canceled.
- Black-Box Testing
- Checking from the outside without seeing the inside. All spec-based techniques fall in this category.
- Test Case
- Each representative case that gets picked. Written as a pair: the input and the expected result.
- Exploratory Testing
- A person poking at what the rulebook never anticipated. Fills the gap for rare combinations spec-based techniques miss.