TDD Amazon Alexa / Echo Skills ?

While TDD and unit testing are different things, TDD often relies on a unit testing framework. I have found no articles about TDDing Amazon Alexa a skill, but here are 3 about unit testing a skill:

• Unit Testing an Amazon Alexa-Skill with Node JS and Jasmine
• Unit Testing Alexa Skills
• Developing Alexa Skills Locally with Node JS - Setting up your Local Environment

Things an "Expert" C Developer Knows: Undefined Behavior

This is the first post in my series: Things an "Expert" C Developer Knows


The 2016 SEI CERT C Coding Standard [free download] gives  this definition of Undefined Behavior:

Behavior, upon use of a nonportable or erroneous program construct or of erroneous data, for which the C Standard imposes no requirements.

An example of an action that causes undefined behavior is signed integer overflow. Professor John Regehr at U of Utah has a blog post that gives several possible examples of what C compilers *could* do with this C statement in a program:

printf ("%d\n", (INT_MAX+1) < 0);

The possibilities Regehr lists include printing 0, 1, 42 or formatting your hard drive. While the latter won't actually happen, undefined behavior can cause data corruption and/or security vulnerabilities.

The CERT C Coding Standard lists. in Appendix C, all undefined behaviors in the current C standard: C11 (more formally known as: ISO/IEC 9899:2011) There are 203.

Since I've mentioned the C11 standard here, I should probably have a Things an "Expert" C Developer Knows post about C standards.