Transcript Supplementary Slides for Software Engineering: A Practitioner's Approach, 5/e

Supplementary Slides for
Software Engineering:
A Practitioner's Approach, 5/e
copyright © 1996, 2001
R.S. Pressman & Associates, Inc.
For University Use Only
May be reproduced ONLY for student use at the university level
when used in conjunction with Software Engineering: A Practitioner's Approach.
Any other reproduction or use is expressly prohibited.
This presentation, slides, or hardcopy may NOT be used for
short courses, industry seminars, or consulting purposes.
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
1
Slide 20
Chapter 18
Software Testing Strategies
Chapter 18 at SEPA textbook
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
2
About testing strategy …
Integrates software test case design methods
into well-planned series of steps that result in
the successful construction of software
Provides a road map that describes
 the steps to be conducted as part of testing,
 when these steps are planned and undertaken, and
 How much effort, time, and resources will be required
Incorporates test planning, test case design,
test execution, and resultant data collection &
evaluation
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
3
Testing Strategy
unit test
system
test
integration
test
validation
test
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
4
Generic characteristics
Testing begins at the component level and
works “outward” toward the integration of the
entire computer-based system
Different testing techniques are appropriate at
different time
Testing is conducted by the developer of the
software and (for a large projects) an
independent test group
Testing and debugging are different activities,
but debugging must be accommodated in any
testing strategy
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
5
Verification & Validation (V&V)
 Verification: the set of activities that ensure that
software correctly implements a specific function
 Validation: a different set of activities that ensure that
software that has been built is traceable to customer
requirements
 Software testing is one element of V&V
 V&V encompasses SQA activities
 FTR, quality & configuration audits, performance monitoring,
simulation, feasibility study, documentation reviews, DB reviews,
algorithm analysis, development testing, qualification testing, &
installation testing
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
6
Strategy
system testing
validation testing
integration testing
Unit testing
Code
design
requirements
System engineering
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
7
Unit Testing
module
to be
tested
results
software
engineer
test cases
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
8
Unit Testing
module
to be
tested
interface
local data structures
boundary conditions
independent paths
error handling paths
test cases
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
9
Unit Test Environment
driver
interface
local data structures
Module
boundary conditions
independent paths
error handling paths
stub
stub
test cases
RESULTS
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
10
Integration Testing Strategies
Options:
• the “big bang” approach
• an incremental construction strategy
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
11
Top Down Integration
A
B
F
top module is tested with
stubs
G
stubs are replaced one at
a time, "depth first"
C
as new modules are integrated,
some subset of tests is re-run
D
E
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
12
Bottom-Up Integration
A
B
G
drivers are replaced one at a
time, "depth first"
C
D
F
E
worker modules are grouped into
builds and integrated
cluster
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
13
Sandwich Testing
A
B
F
Top modules are
tested with stubs
G
C
D
E
Worker modules are grouped into
builds and integrated
cluster
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
14
High Order Testing
validation test
system test
alpha and beta test
other specialized testing
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
15
Validation testing
Test criteria
 Achieved through black box tests
 Demonstrate conformity with requirements
 Two possible condition after testing:
 Function or performance conform to specification & accepted
 A deviation is uncovered and deficiency list is created
Configuration Review
Alpha & Beta Testing
 Alpha test is conducted at the developer’s site by a
customer
 Beta test is conducted at one or more customer sites by
the end-user of the software
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
16
System Testing
Recovery testing
Security testing
Stress testing
Performance testing
++
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
17
Debugging:
A Diagnostic Process
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
18
The Debugging Process
test cases
new test
regression cases
tests
suspected
causes
corrections
results
Debugging
identified
causes
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
19
Debugging Effort
time required
to correct the error
and conduct
regression tests
time required
to diagnose the
symptom and
determine the
cause
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
20
Symptoms & Causes
symptom and cause may be
geographically separated
symptom may disappear when
another problem is fixed
cause may be due to a
combination of non-errors
cause may be due to a system
or compiler error
symptom
cause
cause may be due to
assumptions that everyone
believes
symptom may be intermittent
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
21
Consequences of Bugs
infectious
damage
catastrophic
extreme
serious
disturbing
mild
annoying
Bug Type
Bug Categories: function-related bugs,
system-related bugs, data bugs, coding bugs,
design bugs, documentation bugs, standards
violations, etc.
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
22
Debugging Techniques
brute force / testing
backtracking
induction
deduction
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
23
Debugging: Final Thoughts
1. Don't run off half-cocked, think about the
symptom you're seeing.
2. Use tools (e.g., dynamic debugger) to gain
more insight.
3. If at an impasse, get help from someone else.
4. Be absolutely sure to conduct regression tests
when you do "fix" the bug.
These courseware materials are to be used in conjunction with Software Engineering: A Practitioner’s Approach, 5/e and are
provided with permission by R.S. Pressman & Associates, Inc., copyright © 1996, 2001
24