Designing Software Product Lines for Testability

Software product line (SPL) engineering offers several advantages in the development of families of software products such as reduced costs, high quality and a short time to market. A software product line is a set of software intensive systems, each of which shares a common core set of functionalities, but also differs from the other products through customization tailored to fit the needs of individual groups of customers. The differences between products within the family are well-understood and organized into a feature model that represents the variability of the SPL. Products can then be built by generating and composing features described in the feature model. Testing of software product lines has become a bottleneck in the SPL development lifecycle, since many of the techniques used in their testing have been borrowed from traditional software testing and do not directly take advantage of the similarities between products. This limits the overall gains that can be achieved in SPL engineering. Recent work proposed by both industry and the research community for improving SPL testing has begun to consider this problem, but there is still a need for better testing techniques that are tailored to SPL development. In this thesis, I make two primary contributions to software product line testing. First I propose a new definition for testability of SPLs that is based on the ability to re-use test cases between products without a loss of fault detection effectiveness. I build on this idea to identify elements of the feature model that contribute positively and/or negatively towards SPL testability. Second, I provide a graph based testing approach called the FIG Basis Path method that selects products and features for testing based on a feature dependency graph. This method should increase our ability to re-use results of test cases across successive products in the family and reduce testing effort. I report the results of a case study involving several non-trivial SPLs and show that for these objects, the FIG Basis Path method is as effective as testing all products, but requires us to test no more than 24% of the products in the SPL.

Improved Regression Estimation of a Multivariate Relationship with Population Data on the Bivariate Relationship

Regression coefficients specify the partial effect of a regressor on the dependent variable. Sometimes the bivariate or limited multivariate relationship of that regressor variable with the dependent variable is known from population-level data. We show here that such population- level data can be used to reduce variance and bias about estimates of those regression coefficients from sample survey data. The method of constrained MLE is used to achieve these improvements. Its statistical properties are first described. The method constrains the weighted sum of all the covariate-specific associations (partial effects) of the regressors on the dependent variable to equal the overall association of one or more regressors, where the latter is known exactly from the population data. We refer to those regressors whose bivariate or limited multivariate relationships with the dependent variable are constrained by population data as being ‘‘directly constrained.’’ Our study investigates the improvements in the estimation of directly constrained variables as well as the improvements in the estimation of other regressor variables that may be correlated with the directly constrained variables, and thus ‘‘indirectly constrained’’ by the population data. The example application is to the marital fertility of black versus white women. The difference between white and black women’s rates of marital fertility, available from population-level data, gives the overall association of race with fertility. We show that the constrained MLE technique both provides a far more powerful statistical test of the partial effect of being black and purges the test of a bias that would otherwise distort the estimated magnitude of this effect. We find only trivial reductions, however, in the standard errors of the parameters for indirectly constrained regressors.

Online Dictionary of Invertebrate Zoology: T

tabula tabular tachyauxesis tachyblastic tachygen tachygenesis tachytelic tactic tactile tactoreceptors taenia taeniate taenidium taenioglossate tagma tagmata tagmosis tail tailfan Takakura's talon talus tandem tangent tangoreceptor tanylobous tapetal tapetum tapinoma-odor Tardigrada tardigrades tarsal tarsation tarsite tarsomere tarsungulus tarsus taste tautonomy tautonym taxa taxes taxis taxis taxodont taxometrics taxon taxonomic taxonomist taxonomy tectiform tectostracum tectum teeth teges tegillum tegmen tegmentum tegula tegular tegulum tegumen tegument tegumentary tela telaform telamon telegonic teleiochrysalis telenchium teleoconch teleodont teleology teleotrocha telepod telescope telescopic teletrophic telioderma teliophan telmophage telocentric telodendria telofemur telogonic telolecithal telomitic telophase telophragma telopod telopodite telorhabdions telosonic telostome telosynapsis telosyndesis telotarsus telotaxis telotroch telson template temporal tenacipeds tenaculum tenent teneral tensor tentacle tentacular tentaculocyst tentaculozooid tentilla tentorial tentorium tenuous teratocyte teratogen teratogenesis teratogyne teratology terebella terebra terebrant terebrate teres terete terga tergal tergite tergolateral tergopleural tergopore tergum tergum termen terminal terminalia termitarium termitophile terranes terrestrial terricolous territory tertiary tertibrach tertibrachial tessellate test testaceology testaceous test-cross testes testis testisac testudinate tetanus tetany tetractinal tetractine tetrad tetradelphic tetramerous tetramorphic tetraploid tetrapod tetrapterous tetrasomic tetrathyridial tetrathyridium tetraxon tetraxonid thalassophilous thallus thamnophilous thanatocoenosis thanatosis theca thecae thecal thecate thelycum thelygenesis thelygenous thelyotokous thelyotoky theory thermocline thermophile thermophobe thermoreceptor thermotaxis thickness thigmotactic thigmotaxis thigmotropism third-form thoraces thoracic thoracomere thoracopod(ite) thorax thoraxes thread thylacium thylacogen thyridial thyridium thyroid thysanuriform tibia tibial tibiotarsal tibiotarsus Tiedemann's tiled timbal tinctorial tine tissue tissue titilla titillae titillator tocopherol tocospermal tocospermia tocostome tokostome tomentose tomentum Tomosvary tone tonic tonofibrillae tonus topochemical topogamodeme topomorph topomorphic toponym topotype tori torma tormogen tornote tornus torose torpid torqueate torsion tortuose torulose torus totipotent totomount toxa toxicognath toxicology toxin toxinosis toxoglossate toxoid trabecula trabeculate trabeculated trachea tracheae tracheal tracheate tracheoblast tracheolar tracheoles trachychromatic tract Tragardh's tragus transad transcoxa transcurrent transect transection transformation transient transitional translocation translucent transmission transposed transscutal transstadial transtilla transverse trapeziform trapezium trapezoid trema tremata Trematoda trenchant trepan triact triactinal triad triaene triage triangle triangular triangulate triaulic triaxial triaxon tribe tribocytic trichite trichobothrium trichobranchia trichobranchiate trichocerous trichodes trichodeum trichodragmata trichogen trichoid trichomes trichophore trichopore trichosors trichostichal trichotomous trichroism tricolumella tricomes tricostate tricrepid tricuspid tricuspidate tridactyl trident tridentate trifid trifurcate triglycerides trignathan trigonal trigoneutism trilabiate trilateral trilobate trilocular trimorphic trimorphism Trinominal triordinal tripartite tripectinate triplet triploblastic triploid triquetral triquetrous triradiate triradiates tritocerebral tritocerebrum tritocerebrum tritonymph tritosternum triturate triungulin triungulinid trivial trivium trivoltine trixenic troch trochal trochalopodous trochantellus trochanter trochanteral trochantin trochi trochiform trochlea trocholophous trochophore trochosphere trochus troglobiont troglodytic troglophile trogloxene tropeic trophal trophallactic trophallaxis trophamnion trophi trophic trophidium trophobiont trophobiont trophobiosis trophobiotic trophocytes trophodisc trophogeny trophoporic trophorhinium trophosome trophotaxis trophothylax trophozooid trophus tropis tropism tropotaxis trumpet truncate truncation trunk trypsin tryptic tryptophan tryptophane T-tubule tube tube-feet tubercle tubercula tuberculate tuberculose tuberiferous tubicolous tubifacient tubule tubulus tubus tuft Tullgren tumefaction tumescence tumid tumulus tunic tunica tunicary tunicate turbinate turgid turreted turriculate tychoparthenogenesis tylasters tylenchoid tyli tyloid tyloides tylosis tylostyle tylote tylus tymbal tympanal tympanal tympanic tympanum Tyndall type typhlosole typologist typolysis typostasis