cppcon_add_library(basic LIBRARIES Asio::asio) add_subdirectory(tests)

with Approval Tests Clare Macrae (She/her) clare@claremacrae.co.uk 16 September 2020 CppCon (Online)2 Audience: Developers testing Desktop GUIs, including Qt-based ones Approval Tests: claremacrae tations.html3 Contents •Introduction •Qt –Setting Up Testing –Error-prone Things –Approval Tests •Extras –Tools –Summary4 About Me • Scientific C++ and Qt developer since 1999 • My mission: mission: Sustainable and efficient testing and refactoring of legacy code – Co-author of “Approval Tests for C++” • Consulting & training via “Clare Macrae Consulting Ltd” – claremacrae.co.uk • All links

Behavior-driven Tests for Microservices-based Algo Trading System Summary : Introduction : This poster will introduce a test framework we use at Bloomberg to enable behavior-based tests in natural language often non-trivial to automate the system-level tests with external dependencies. Controlling external dependencies are especially important for algo tests since certain algo behaviors require hard-to-produce condition. ● Fully automated : Running tests are integrated into CI so algo behaviors are regressed for any dependent code change. ● Natural language layer: Tests are written in natural language so

and Mike Shah (tomorrow): Back To Basics, Debugging and Testing Chip Hogg (Wednesday), Making Hard Tests Easy (Robotics Track) Xiaofan Sun (Thursday): Mix Assertion, Logging, Unit Testing and Fuzzing Pete 3Learning Unit Testing CppCon 2015: T. Winters & H. Wright “All Your Tests are Terrible..." 4Rule 0 Write unit tests 5Part 0: Basics of the Basics Unit testing is the act of testing the correctness correctness of your code at the smallest possible unit: the function. Unit tests are small, automated, stand alone executables that perform unit testing on your code. Part 0: Basics 6auto abs(int x) ->

Google Test filter = FifoTest/0.* [==========] Running 6 tests from 1 test suite. [----------] Global test environment set-up. [----------] 6 tests from FifoTest/0, where TypeParam = Fifo1 [ RUN (0 ms) [----------] 6 tests from FifoTest/0 (0 ms total) [----------] Global test environment tear-down [==========] 6 tests from 1 test suite ran. (0 ms total) [ PASSED ] 6 tests.16 cfrasch@Charles- Google Test filter = FifoTest/0.* [==========] Running 6 tests from 1 test suite. [----------] Global test environment set-up. [----------] 6 tests from FifoTest/0, where TypeParam = Fifo1 [ RUN

Ruth (he/him) brian.ruth@garmin.comPart 0: Legacy Code• It works* • It may not have tests, but has been tested • Documents all the decisions and problems encountered in its lifetime • It every feature Write Automated tests and run them continuously Test the change you just made Testing StrategiesTest Everything on every feature Write Automated tests and run them continuously Test every feature Write Automated tests and run them continuously Test the change you just made Testing StrategiesTest Everything on every feature Write Automated tests and run them continuously Test

Aurora Innovation Maintaining Software Reading Refactoring Upgrading Migrating Debugging Adding tests Writing documentation Resolving technical debt “The only constant in life is change.” - Heraclitus5 software, how could we stay productive and safely introduce frequent changes? Implement high-level tests and continuously run them at scale to cover real-world system behaviors with reasonable degree of outer loops Fast feedback cycles boost development con�dence and productivity. Moving high-level tests out of the developer loop results in slow and inef�cient application life- cycles.16 Aurora Innovation

g(nullptr); } % clang++ -std=c++20 tests/c++/sfinae-ambiguous.cpp tests/c++/sfinae-ambiguous.cpp:10:5: error: no matching function for call to 'g' g(nullptr); ^ tests/c++/sfinae-ambiguous.cpp:5:6: t) -> decltype(f(t)) { ^ 1 error generated.% `cwhy --wrapper` -std=c++20 tests/c++/sfinae-ambiguous.cpp void f(void*) {} void f(char*) {} template auto g(T t) g(nullptr); } % clang++ -std=c++20 tests/c++/sfinae-ambiguous.cpp tests/c++/sfinae-ambiguous.cpp:10:5: error: no matching function for call to 'g' g(nullptr); ^ tests/c++/sfinae-ambiguous.cpp:5:6:

is by standing upon the shoulders of giants. -- Isaac Newton T. Winters and H. Wright, All Your Tests Are Terrible... CppCon 2015 Fedor Pikus, Back to Basics: Test-driven Development CppCon 2019 Kevlin 2Properties of Good Tests 1. Correctness 2. Completeness 3. Readability 4. Demonstrability 5. Resilience 0. Existence! Remember, bad tests are almost always better than no tests! Easy to run Fast testing) Forces better design ("design for testability") Avoids tight coupling to implementation Unit tests are also examples and documentation 4Object Oriented testing Let's unit test this class // Cup

when OTHER people make mistakesTestability 14Testability 15 • Unit TestsTestability 16 • Unit Tests • TDDTestability 17 I often struggle with how to make my classes testable. I sometimes find that more template parameters. I could keep going along this line but I won't.Testability 22 • Unit Tests • TDDTestability: Hidden State 23Testability: Hidden State 24 /** * The crux of this pattern Knuth on Unit Tests In that vein, today’s developers frequently build programs writing small code increments followed by immediate compilation and the creation and running of unit tests. What are your