COM6506 Resit Assessment
Tasks
There are two tasks - one on Fault Tree Analysis, and one on Metamorphic Testing. Both are evenly
weighted (50 marks each).
1. Fault Tree Analysis
Consider the following description of a system.
An airplane manufacturer has developed a new aircraft with an advanced autopilot system. Once
the pilot has entered their destination coordinates, the autopilot system will automatically pilot the
aircraft to the destination. The autopilot system incorporates a weather analysis component, which
downloads weather data via a satellite data link to a weather station. It runs this data through an
onboard data-processing unit, which provides warnings of any potential adverse weather conditions
that might affect the flight. These are passed to a route-planning component, which dynamically
alters the route to avoid the adverse weather. The route-planner is connected to a GPS component
and an altitude sensor so that the aircraft is able to determine its own location and altitude. It is
also connected via a separate data link to the Air Traffic Control centre, to download the flight plans
for any aircraft in the area, so that any flight plans avoid collisions. As a backup, the system is also
connected to a radar onboard the aircraft. This is only capable of detecting other aircraft at short
notice, and alerts the pilot of these via a loud buzzer, so that they can override the autopilot.
(a) Use this system description to build a simple architectural diagram of the system. This can
be a straightforward entity-relationship diagram, indicating all of the key components and the
data or information links between them.
15 marks
(b) Build a fault-tree from the architectural diagram. This should contain AND and OR-gates,
and illustrate all of the faults that might arise from failures highlighted within the architectural
diagram. You should limit the scope to the autopilot system as described above (specifically,
faults that might arise within the hardware and software on the aircraft).
35 marks
2. Metamorphic Testing
(a) Provide a description of how Metamorphic Testing works (between 200 and 300 words in
length).
10 marks
(b) Consider the natural logarithm function as, for example, implemented in Java:
https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#log-double-
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Use Metamorphic Testing to devise three test sets for this function. For this you should identify
three different metamorphic relations. You can use the following webpage (for example) as a
starting point:
https://en.wikipedia.org/wiki/List_of_logarithmic_identities
In your submission, for each metamorphic relation clearly describe and justify it. For the
corresponding test sets, write out 5 test cases per test set (the inputs and the expected
outputs).
40 marks
Submission instructions
Submit your assignment as a PDF document, by 10am 1st of October.
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