Stack Overflow question ‘Inputting list of passwords in a class’ is more interesting as an object-oriented design (OOD) exercise than as a debugging exercise, but it also provides an opportunity to practise some Python programming. The requirements identified in the problem are: represent a set of credentials comprised of a username and a password; represent …
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Undefined behaviours in the C language confuse many beginners. As an occasional C programmer I am also baffled when I encounter them—as happened with this code that I wrote in an Arduino sketch. static void get_input(String prompt, void* const input, void (*parse_func)(void* const), int (*validate_func)(const void* const)) { while (!validate_func((const void* const)input)) { Serial.println(prompt); while …
As a fun way to improve my C, I started programming the Arduino using Atmel Studio instead of the friendlier Arduino IDE. Below is my very first program. It blinks a red LED and a white LED according to a preset pattern. #define F_CPU 16000000UL #include <avr/io.h> #include <util/delay.h> struct Led { int pin; int …
We use smtpop.dll in one application to retrieve email from a POP3 mailbox. Today we had to connect to a mailbox over SSL, which smtpop.dll does not support. Our code to retrieve email is abstracted behind a façade class, so I expected to simply substitute a new library for smtpop.dll and to call new methods. …
From http://thoughtworks.fileburst.com/assets/technology-radar-jan-2014-en.pdf: We continue to see teams run into trouble using JSF– JavaServer Faces — and are recommending you avoid this technology. Teams seem to choose JSF because it is a J2EE standard without really evaluating whether the programming model suits them. We think JSF is flawed because it tries to abstract away HTML, CSS …
This morning a deployment failed catastrophically. One of the scripts for upgrading the database caused several objects to be dropped unexpectedly. We restored the database from backup, corrected the script, and repeated the deployment, which was successful. We now had to do a retrospective to learn what went wrong and how to avoid it in …
Robert Binder’s Testing Object-Oriented Systems book sits permanenly on my desk. At over 1500 pages long, it is almost a never-ending read, but from time to time I pause to read a few choice chapters. Binder also wrote about the compliance testing of Microsoft’s court-ordered publication of its Windows client-server protocols in 2012. An interesting …
I try to avoid the Arrange-Act-Assert (AAA) pattern for unit tests. I find that with multiple test methods depending on the same starting conditions, the ‘arrange’ code becomes repetitive, which makes tests tedious to write and difficult to maintain. My preferred approach is to set one test fixture per test class, the test fixture being …
Interpreted literally, unit testing means testing each class individually. Complete isolation is, however, difficult given that a class typically interacts with other classes. Therefore, for this definition of unit testing to hold, collaborating classes must be replaced with fakes in a test. But developers confront two main problems when using these mock objects. First, tests …
The purpose of BASE64 is to communicate binary data as text, using only characters that exist on most computer platforms. These safe characters form the BASE64 alphabet and are the letters A to Z and a to z, the numerals 0 to 9, and the characters / and +. Other ways of representing bytes as text exist. …