Non-tested code

Though many articles have been written and discussions have been initiated at various developers' conferences on different types of testing—test-driven development, behavior-driven development, and acceptance test-driven development—it is very concerning that there are developers that continuously develop and ship software applications that are not thoroughly tested or tested at all.

Shipping applications that are poorly tested can have catastrophic consequences and maintenance problems. Notable is NASA's Mars Climate Orbiter launched on December 11, 1998 that failed just as the orbiter approached Mars, due to a software error caused by an error in conversion where the orbiter's program code was calculating a metric in pounds instead of newtons. A simple unit testing of the particular module responsible for calculating the metrics could have detected the error and maybe prevented the failure.

Also, according to the State of Test-First Methodologies 2016 Report, a survey of the adoption of test-first methodologies of more than 200 software organizations from 15 different countries, conducted by a testing services company named QASymphony, revealed that nearly half of the survey respondents had not implemented a test-first methodology in the applications they had developed.