Software Testing. Integration Testing. Beat Fluri. software evolution & architecture lab

Transcription

1 Software Testing Integration Testing Beat Fluri software evolution & architecture lab

2 V-Model Specification Implementation User needs Delivery System Spec System Integration Test Subsystem Design/Spec Subsystem Unit Test Unit Design/Spec Unit 2

3 Integration Testing Integration testing is a search for components faults that cause intercomponent failures Breaking up component isolation step-by-step Integration strategy Which components are the focus of the integration test? In what sequence should component interfaces be exercised? Integration testing in object-oriented development begins early Within a class (integrating methods) Within a class hierarchy (integrating superclasses) Between a client and its server Within a package (integrating classes)... 3

4 Dependency Analysis Integration strategy follows sequences in which components have to be tested Dependency analysis among components is used to define the sequences Dependency analysis: approach Take component diagram, e.g., UML class diagram Make topology (i.e., directed graph) of the dependencies 4

5 Dependency Analysis P CC C * O * M A * * CP S 5

6 Dependency Analysis CC P C O A M CP S depends on 6

7 Big Bang Integration Demonstrate stability by attempting to exercise an entire system with a few test runs Integrate all components at once Monolithic system Components tightly coupled No doubles are necessary Problems Fault locations are difficult to find Big bang test suites are usually to small to reveal all interface faults Try to avoid big bang integration! 7

8 Big Bang Integration Driver CC P C O A M CP S 8

9 Bottom-up Integration Demonstrate stability by adding components to the system under test in uses-dependency order, beginning with components having the fewest dependencies Approach Test leaf components in dependency graph with drivers for each leaf. Use doubles when necessary Repeat: test components on the next level; until the entire system is tested 9

10 Bottom-up Integration CC P C O A M CP S Driver 10

11 Bottom-up Integration CC P C Driver O A M CP Driver S 11

12 Bottom-up Integration Advantages Early integration of leaf components Parallel development on components in subtrees of dependency graph Reduces the number of doubles (only for cycles) Disadvantages Many drivers have to be developed Interaction testing is limited to collaborations implemented in the component (root of subtree) Postpones checking critical control interfaces and collaborations until the end (root of dependency graph) 12

13 Top-down Integration Demonstrate stability by adding components to the system under test in control hierarchy order, beginning with the top level control objects Approach Test component(s) at the highest level first. Use doubles for lower level components Continue in a breath-first order at each level in the dependency graph until all components are integrated 13

14 Top-down Integration Driver CC P C O A M CP S 14

15 Top-down Integration Driver Driver CC P C O A M CP S 15

16 Top-down Integration Advantages Early demonstration of end-to-end functionality Fewer drivers necessary than with bottom-up integration Test cases can be reused to drive lower-level tests Disadvantages Development and maintenance of doubles Test cases in high-level components may not be sufficient for lower-level components 16

17 Collaboration Integration Demonstrate stability by adding sets of components to the system under test that are required to support a particular collaboration Approach Map collaborations onto the dependency graph Choose a sequence in which to apply testing on collaborations Test collaboration in the chosen sequence 17

18 Collaboration Integration CC P C O A M CP S 18

19 Collaboration Integration CC P C Driver O A M CP S 19

20 Collaboration Integration Driver CC P C O A M CP S 20

21 Collaboration Integration Driver CC P C O A M CP S 21

22 Collaboration Integration Advantages Few drivers and doubles necessary Focus on end-to-end functionality; useful for system scope testing Reuse of collaboration integration test suite for system test Disadvantages Inter-collaboration may not be tested thoroughly Participants in a collaboration are not exercised separately (big bang) Probably many doubles for testing initial collaborations 22

23 Backbone Integration Combination of top-down integration, bottom-up integration, and big bang integration to verify interoperability among tightly coupled subsystems Used, for instance, for embedded system applications Backbone provides services that are essential for running tests and the application Creating doubles for the entire backbone would be impractical Approach Test each component in backbone in isolation and do a bottom-up integration or big bang integration of the backbone Do a top-down integration on the application control components 23

24 Backbone Integration Backbone Bottom-up Integration Top-down Integration 24

25 Backbone Integration Advantages Mitigates the disadvantages of top-down and bottom-up integration Disadvantages Doubles and drivers are necessary 25