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SFWR ENG 3S03 Summary

  • Teacher: Dr. Khedri
  • Winter 2015
  • McMaster University
  • Primary Author: Kemal Ahmed

Requirements Hierarchy

##Challenges of Software Testing

  • Budget pressure
  • Project planner underestimates costs of a stage
  • Estimated budget was never approved
  • Safety is required before features
  • Time pressure
  • Lower time pressure with more developers
  • Can happen if there are too many delaying factors
  • Managing testing
  • Those who do testing need to be qualified
  • How to test?
    • What?
    • When?
    • How much resources?
  • Ambiguous Requirements, documentation, etc.
  • More environments
  • More languages
  • More layers

##Measurement

Metric: a quantitative attribute

Measurement:

Benchmark: a standard unit of measurement

Measure: to determine the measurements of something

Symbol: a short representation of a unit of measurement

###What to measure?

Measure everything useful to achieving your goals.

Sometimes, it can be difficult to describe an attribute using a metric, e.g. colour in nanometres.

Sometimes you want to measure something that is a combination of attributes.

###Types of measurements

Deductive: directly measured

Inductive: determined by putting different deduced information together

##Models for testing

Often, it's not enough to simply say whether something is good or bad, so we define a model that scores it using a combination of metrics that give a quantitative score. That includes:

  • Quality of Requirements
  • Management issues
  • Quality of work
  • Productivity
  • Cost
  • Effort:
  • Size: lines of codes & function points
  • Productivity:
  • etc.

Models demonstrate:

  1. Things whose effects are neglected
  2. Things that affect that model that you didn't consider.
  3. Things that you did consider

Gib's Fuzzy Testing:

Khedri's words of wisdom: when the company at your internship is doing stuff in a non-systematic way, do what you can to change it.

COnstructive COst MOdel (COCOMO):

A->B: h^{nf}
A->B: h

$A=(A,F,R)$

$h^{m_R}$ is a subset of P

(S,F,R)

A structure is algebraic iff $R=0$ (S,F)

A structure is relational iff $F=0$ (S,R)

####e.g. Graphs

$$G = (V,E) =( {a,b,c,d},{a,d},{b,c},{a,b},{d,c},)$$

A = V F = 0 $R = {E}$

$h \left ( f\left ( a_1,...,a_{n_y} \right ) \right ) = g \left (h^{n_f} \left ( a_1,..., a_{n_y} \right ) \right )$

####Bijection : A function + injective + subjective

Every definition is reached once

####Surjective : lala

  • Not injective
  • Could be a measurement mapping

####Injective : noonoo

Not surjective

###Evaluating software

####Likert Scale : A reliability scale of software where someone selects agreement from a set of {strongly agree, agree, neither, disagree, strongly disagree}

####Forced Ranking : Rank the options from 1 (best) to n (worst).

####Verbal Frequency : Select failure frequency from the set of {Always, Often, Sometimes, Seldom, Never}.

####Ordinal Software : brb

####Comparative Scale : Pick integer from 1---n from Superior to Inferior

####Numerical Scale : Pick integer from 1---n from Unimportant to Important

####Statement Type : blah

###More...

####Homomorphism : A homomorphism or representation is a mapping from $A$ to $B$ that reserves the operations of $A$ to the corresponding in $B$. It also weakly reserves the relations in $A$ to their corresponding in $B$.

i.e. a structure from $A$ to $B$ that satisfies rule 2 (function) and 3 (relation). $$h: A \rightarrow B$$

: An application of this concept is described in a book called Calculus is Algebra by William Hatcher.

The connection between the real $(S, F, R)$ and mathematical worlds $\mathbb{R}_R, F_R, R_R$, using empirical analysis, $\mu_1$.

####McCabe Threshold

$\eta$ measures:

  • fault-prone
  • maintainability
  • Range: 0-10

####Direct Measurement

Direct Measurement: ga

Examples: *

####Reliability Model

$$F(t) = 1 - e^{-\left (N - i + 1 \right )at}$$

###Measurement Scales

Scale =

Algebraic Difference Structure:

####Nominal : oogachacka

####Ordinal : transitivity

####Interval : comparing stuff on the same interval

  • Obsolete system, but we should know it 😒

####Ratio : hee hee