Quickstrom: property-based acceptance testing with LTL specifications

We present Quickstrom, a property-based testing system for acceptance testing of interactive applications. Using Quickstrom, programmers can specify the behaviour of web applications as properties in our testing-oriented dialect of Linear Temporal Logic (LTL) called QuickLTL, and then automatically test their application against the given specification with hundreds of automatically generated interactions. QuickLTL extends existing finite variants of LTL for the testing use-case, determining likely outcomes from partial traces whose minimum length is itself determined by the LTL formula. This temporal logic is embedded in our specification language, Specstrom, which is designed to be approachable to web programmers, expressive for writing specifications, and easy to analyse. Because Quickstrom tests only user-facing behaviour, it is agnostic to the implementation language of the system under test. We therefore formally specify and test many implementations of the popular TodoMVC benchmark, used for evaluation and comparison across various web frontend frameworks and languages. Our tests uncovered bugs in almost half of the available implementations.Comment: 13 pages, this is a technical report of a paper to appear at Programming Languages Design and Implementation (PLDI 2022

Analysis of a New Plate Thermometer - The Copper Disc Plate Thermometer

Two temperatures govern heat transfer to a surface of a solid body. One is the gas temperature which can be measured with thermocouples (TC) and the other the black body radiation temperature. The latter can also be expressed as the incident radiant heat flux. It is difficult to measure as radiometers cannot be used under hot fire conditions. Indirectly the radiation temperature can be obtained by measuring the Adiabatic Surface Temperature (AST) with plate thermometers (PT) for example as defined in the fire resistance furnace standards EN 1363-1 and ISO-834-1 combined with measurements of gas temperature with thin TC. In the test reported here a smaller gauge is used to measure adiabatic surface temperature at surfaces. It has been named copper disc Plate Thermometer (cdPT). Then a thin copper disc with an attached TC is mounted flush at the surface to obtain the AST in e.g. cone calorimeters according to ISO 5660. A main advantage of the cdPT is that it can record the AST before as well after a material has ignited. It can thereby be used to indicate ignition as well as continue recording the thermal exposure thereafter when ignition occurs the cdPT reacts immediately by displaying a quick temperature rise.Godkänd; 2015; 20160823 (alebys)</p