Specification-oriented methods, which are also caled blackbox methods are utilized for defining test-cases based on specifications and user requirements. The content of components are not evaluated for these kinds of tests, which reduces efforts and complexits. Only inputs and outputs of components are evaluated. Details about Blackboxes can be found within Software Architecture.
Equivalence Class Formation and Analysis
Decomposes a set of input/output data into subsets so that the test is each value equivalent to the test of another value of the same class. This method assumes, that a test object in several equivalence class is behaving functionally consistent for any test data. Testing one reprensetative data set of an equivalence class represents the whole class. Next to valid inputs, also invalid inputs must be considered (negative testing).
Define base-classes
Define a defiition scope and create classes of valid and
Refine classes
Refine new classes for each class, which must be processed differently.
Select representatives
Define a testcase for each representative equivalence class.
This kind of analysis requires one test-case per class for positive cases. Negative cases can extend the test-scope (e.g. special characters, empty strings, null-values, etc.). If you have numeric limits, you should evaluate the Limit Value Analysis for extending your test scope.
In case of equicalence tables, combinatorics can be used to reduce the amount of test-cases by defining, e.g. by selecting negative tests, which cover all combinatoions. In the example below only 4 instead of 6 test cases are required:
Limit Value Analysis
Limit Value analysis are utilized to enhance given equivalence class analysis, as failures are concentrated at those values. This kind of analysis is done by defining lower and upper limits for given areas and verifying these limits including the smallest possible increment (positive and negative) of that value.
These values are considered for test-cases and help identifying error-prone values within software implementations. For each limit three (3) test-cases are required, which also cover negative tests (values outside of valid limits).
Functional Decision Table Test
Decision tables are another testing element, when multiple parameters must be considered for outcomes. They are commonly used for Operation Decision Management (ODM) and BPEL / Work-Flow engines:
Condition Assessment
Scenario: Age-Based Movie Ticket Pricing
A cinema offers different ticket prices based on age:
- Child (0-12 years): $5
- Teen (13-17 years): $8
- Adult (18-64 years): $12
- Senior (65+ years): $7
- Invalid Age (<0 or Non-Numeric): Rejected