1. Marius Skudžinskas IFM-02
Sandwich strategy
Marius Skudžinskas IFM-02

2. Content Sandwich strategy what‘s that? How does it work? Pros and cons
Modified Sandwich strategy what‘s that?

3. Sandwich strategy what‘s that?
It‘s a combination of top down and bottom up testing strategies. It‘s purpose is compromise usage of top down and bottom up strategies .

4. How does it work? The system is view as having three layers
A target layer in the middle
A layer above the target
A layer below the target
Testing converges at the target layer
How do you select the target layer if there are more than 3 layers?
Heuristic: Try to minimize the number of stubs and drivers

5. How does it work? (2)

6. How does it work? (3) Test E Test B, E, F Bottom Layer TestsC D G F E
Layer I
Layer II
Layer III
Test E
Test B, E, F
Bottom
Layer
Tests
Bottom up testing
Test F
Test
A, B, C, D,
E, F, G
Test G
Test D,G
Test A,B,C, D
Test A
Top
Layer
Tests
Top down

7. Pros and Cons of Sandwich Testing
Top and Bottom Layer Tests can be done in parallel.
Does not test the individual subsystems thoroughly before integration.
Solution: Modified sandwich testing strategy.

8. Modified Sandwich Testing Strategy
It‘s a better version of Sandwich Testing Strategy.

9. How does it work? Test in parallel:
Middle layer with drivers and stubs
Top layer accessing middle layer (top layer replaces drivers)
Bottom accessed by middle layer (bottom layer replaces stubs)

10. How does it work? (2) Double Test I Test B Test E Triple Test I
Test A,C A B C D G F E
Layer I
Layer II
Layer III
Test F
Test E
Test B
Test B, E, F
Triple
Test I
Test D,G
Double
Test II
Test
A, B, C, D,
E, F, G
Test G
Test D
Test A
Test C

11. Pros and Cons of Modified Sandwich Testing
Takes less time than top down and bottom up testing. Bėcouse they are used partial.
It still needs drivers and stubs.

12. Questions Sandwich strategy what‘s that?
How many layers system has in Sandwich strategy?
How do you select the target layer if there are more than 3 layers?
What‘s better Sandwich strategy or Modified sandwich strategy? Why?