What is "testing"

Of Wikipedia:

Software testing is an investigation conducted to provide information on the quality of the product or service under test to interested parties. Software testing can also provide an objective and independent view of software to enable business to appreciate and understand the risks of software implementation.

Testing techniques include, but are not limited to, the process of running an application program or intending to encounter software errors (errors or other defects).

Software testing can be defined as the process of validating and verifying that a software program/application/product:

1. meets the design and development requirements;
2. works as expected;
3. can be implemented with the same characteristics.

Software testing, according to the test method used, can be implemented at any time in the development process. However, most of the testing effort occurs after the requirements have been defined and the coding process has been completed. As such, the test method is governed by the adapted software development methodology.