Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
1999-05-26
2002-05-07
Baderman, S. (Department: 2184)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C714S033000, C717S152000
Reexamination Certificate
active
06385741
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method and an apparatus for selecting test sequences, and in particular to a method and an apparatus for selecting test sequences in a software which has a specification prescribed by state transitions.
2. Description of the Related Art
In recent years, the selection of test sequences in testing a software which has a specification prescribed by state transitions has been generally performed by manual works. A procedure for such a manual selection of test sequences will be described referring to
FIGS. 22-25
.
A specification prescribed by state transitions can be composed of the combination of a preceding state Sx, an event Ey, and a subsequent state Sx+1 as shown in FIG.
22
.
FIG. 23
illustrates an example of a telephone specification, as a general one, which is composed of the combination of the state transitions.
A state of “idle” (S
10
) in which a receiver is hanged up is an initial state (=preceding state). If an event of “off-hook” (E
10
) in which the receiver is picked up occurs, the preceding state (=present state) has a transition to a state of “dial tone” (S
20
) (=subsequent state).
This is one example of a state transition.
When the receiver is hanged up in the state of “dial tone” (S
20
), an event of “on-hook” (E
22
) occurs and the present state returns to the initial state (S
10
). If ordinary numerals are dialed (E
20
) in the state of “dial tone” (S
20
), the present state has a transition to a state of “call” (S
30
). If the call is not answered from the other end of the line, the present state returns to the initial state (S
10
) through an event of “on-hook” (E
31
). If the call is answered through an event of “response” (E
30
), the present state has a transition to a state of “communication” (S
40
), and if an event of “on-hook” (E
40
) occurs after the state of “communication”, the present state returns to the initial state (S
10
).
If special numerals such as “100” are dialed (E
21
) in the state of “dial tone” (S
20
), the present state has a transition to a state of “special call” (S
50
). If the call is answered through an event of “response” (E
50
), the present state has a transition to a state of “special communication” (S
60
). In the state of “special call” or “special communication” (S
50
or S
60
), the communication line will not be released even if an event of “on-hook” (E
51
or E
60
) occurs. Instead, the present state has a transition to a state of “reserve” (S
70
). If a “compulsory call” is answered back from the other end of the line (E
70
), the present state has a transition to a state of “reverse call” (S
80
). If the call is answered through an event of “response” (E
80
), the present state returns to the state of “special communication” (S
60
).
In the state of “special communication”, “reserve” or “reverse call” (S
60
, S
70
or S
80
), if an event of “release” (E
61
, E
71
or E
81
) occurs, the present state returns to the initial state (S
10
).
An example of the specification having the combination of the state transitions in
FIG. 23
is expressed in the form of a tree as shown in FIG.
24
. It is to be noted that the events are omitted in FIG.
24
. If the specification can be transformed into such a tree-structured combination of state transitions, test sequences can be extracted by adopting a pre-order traversal algorithm. The test sequences which can be extracted from the tree shown in
FIG. 24
can be divided into six as shown in
FIGS. 25A-25F
.
Among the extracted test sequences, the selection of test sequences for which an actual test should be performed is done by an examiner in charge based on his experience. When selecting test sequences, it is general that all state transitions are tested at least once without omission in which a state transition in a normal mode which is called a “main sequence” is preferentially tested with the combination of state transitions of “illegal sequences”.
Such a manual selection of test sequences, when performed by an inexperienced examiner, may lead to a decrease in test efficiency due to selecting many unnecessary test sequences or to a decrease in test reliability due to failing to select necessary tests on the contrary. Also, even when performed by an experienced examiner, in case of a complicated system, the selection requires much time and causes human errors with a high possibility.
Specifically, a primary problem in the selection of test sequences arises when a specification composed of the combination of state transitions is transformed into a tree. Namely, although every node in a tree must have only one parent node, a specification composed of the combination of normal state transitions includes junctions (see {circle around (
1
)} in
FIG. 23
) in which a node has a plurality of parent nodes and loops (see {circle around (
2
)} in FIG.
23
). Therefore, an experienced examiner is required to remove the junctions and the loops with appropriate means to transform the combination of state transitions into a tree-structure.
A secondary problem is that it is hard to appropriately select test sequences to be actually tested among all of the test sequences which can be extracted logically. Namely, since it is not practical to test all of the test sequences under the restrictions of a test term or man-hours, it is required to take time for sequentially selecting the test sequences to be actually tested in order of higher priority.
SUMMARY OF THE INVENTION
It is accordingly an object of the present invention to provide a method and an apparatus for transforming a given specification which is composed of the combination of state transitions into a tree-structure having removed therefrom junctions and loops, and for efficiently selecting appropriate test sequences.
[1] A method for selecting test sequences according to the present invention for the achievement of the above mentioned object, as schematically illustrated in
FIG. 1
, comprises a first step S
1
for preparing tree-structured state transition data associated with state transition weights from state transition data, a second step S
2
for extracting test sequences from the tree-structured state transition data, and a third step S
3
for repeating processes of determining averaged weight for each of the test sequences, selecting a test sequence by which the average is maximum, and decrementing the weights contained in the selected test sequence by one unit to prioritize the test sequences.
Namely, in the first step S
1
, the tree-structured state transition data associated with state transition weights are prepared based on state transition data inputted as an aggregation of state transitions (see
FIG. 22
) and state transition weights which are inputted and set to have higher values for state transitions of more importance.
If the tree-structured state transition data are prepared, junctions and loops can be removed from the state transition data and all of the test sequences can be extracted. Therefore, in the second step S
2
, for example, a pre-order traversal algorithm is applied to the tree-structured state transition data, thereby extracting all of the test sequences.
For all of the test sequences extracted in the second the step S
2
, priorities among the test sequences are obtained in the third step S
3
.
Namely, in the third step S
3
, for all of the test sequences, the total of the state transition weights contained in each test sequence is divided by the number of the state transitions to obtain an averaged weight. The averaged weights for all of the test sequences are compared to one another, and the test sequence with the highest averaged weight is selected. Then the weights contained in the selected test sequence are decremented by one unit. Such processes are repeated until all priorities among the test sequences are determined.
Based on the priorities among the test sequences as obtained above, it is possible to omit unnecessary tests and perform only necessary tests, thus e
Baderman S.
Fujitsu Limited
Rosenman & Colin LLP
LandOfFree
Method and apparatus for selecting test sequences does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for selecting test sequences, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for selecting test sequences will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2871694