- Information
- AI Chat
CSC1015F Testing and Debugging
Computer science1015 (CSC1015F)
University of Cape Town
Preview text
Errors What is an error?
- when your program does not behave as intended or expected.
What is a bug?
- An error
Debugging
- the art of removing bugs
Types of Errors - When (1)
- “Compile” time error
- discovered when program is checked by the Python interpreter, before its run.
- a result of improper use of Python language
- usually Syntax Errors
- e.
Types of Errors - When (2)
Run-time Error
Program structure is correct, but does not execute as expected
e. x = 0 y = 15/x
Examples of Python runtime errors
division by zero
performing an operation on incompatible types
using an identifier which has not been defined
Types of Errors - Why (1)
- Syntax error
- Program does not pass checking/ compiling stage
- improper use of python language
- e. product = x y
grammaticalerrorsmissingfullstopspellingmistakeetc product
Imissing 11 operator
divisionbyzero
multiplyinganumberwithastring 1 character
- Common Python syntax errors
- leaving out a keyword
- putting a keyword in the wrong place
- leaving out a symbol, such as a colon, comma or bracket
- misspelling a keyword
- incorrect indentation
Types of Errors - Why (2)
- Logic Error
- program passes checking/ compiling and runs but produces incorrect results or no results - because of a flaw in the algorithm or implementation of algorithm
- e. product = x + y
singleequalsigninsteadofadoubleequaltosign
loopsfunctionsetc
akasemanticerror
statementsareincorrect
there'snoerrorintheprogramitselftheerrorisinthelogic
shouldbesum
oroperatorshouldbetx
programwillexecutebutitdoesn'tprovideyouwiththecorrectoutput incorrectoutput
Examples
LogicErroruT
SyntaxerroirT
- Random testing
- a subset of values in the input domain is used for testing
- important to ensure that values are distributed over input domain
- can use random number generation
Equivalence Classes & Boundary Values
Equivalence classes: Group input values into sets of values with similar expected behaviour and choose candidate values e. (100, -90, 10000) & (40000, 100000)
Boundary value analysis: choose values at, and on either side of, the boundaries of the equivalence classes- e. 9999, 10000, 10001
1
generator
defthresholdCrab
itrainoooovaltoooo
t
returnval
2 classes 10000 ibelow Tabore 10000
e 1,23,45,
checkingvalueat 5 test 446
Incorrectanswerfor 2 cases
Path testing
create test cases to test every path of execution of the program at least once.
Statement coverage
testwithvaluesoneitherside
Differentpaths
ifstatementtrueorfalse
conditions
forloopvalueis
withinthelooporoutsidetheloop
Whiteloopin 1 outofthelooptrueorfalse
conditions
eachstatementisexecutedatleastonce
Write a program to convert decimal numbers to binary Decimal to Binary Conversion
Notimportantrightnowjustwanttotest
Equivalenceclasses valueslessthanzero decimalslessthanzero
numbersfromzeroup
Boundaryvalues io 1
Statementcoverage
singlevalueissufficient 1101
Pathcoverage
5 to
CSC1015F Testing and Debugging
Course: Computer science1015 (CSC1015F)
University: University of Cape Town
This is a preview
Access to all documents
Get Unlimited Downloads
Improve your grades
