Assert

An assertion; a section of source code which tests whether an expected condition is true.

To declare with assurance or plainly and strongly; to state positively.

"He would often assert that there was life on other planets."

To use or exercise and thereby prove the existence of.

"Salman Rushdie has asserted his right to be identified as the author of this work."

To maintain or defend, as a cause or a claim, by words or measures; to vindicate a claim or title to

"to assert our rights and liberties"

To specify that a condition or expression is true at a certain point in the code.