In COMPUTER-SCIENCE<\/a> and SOFTWARE-ENGINEERING<\/a>, an ASSERTION<\/a> is a statement that a predicate is expected to be true at a specific point during program execution. If the predicate evaluates to false, the program typically terminates or throws an error, indicating a bug in the logic. Assertions are a fundamental tool for DEBUGGING<\/a> and maintaining code quality.<\/p> The concept is a core component of DESIGN-BY-CONTRACT<\/a>, a methodology pioneered by BERTRAND-MEYER<\/a>. In this context, assertions are used to define preconditions, postconditions, and class INVARIANT<\/a> definitions. By explicitly stating these assumptions, developers can ensure that the SOURCE-CODE<\/a> behaves as intended during the development cycle.<\/p> Most modern programming languages provide built-in support for assertions. In the C-PROGRAMMING-LANGUAGE<\/a>, the Unlike error handling mechanisms such as EXCEPTION-HANDLING<\/a>, assertions are generally not intended to handle recoverable runtime errors like missing files or network timeouts. Instead, they catch developer errors that should never occur in a correctly functioning system. For further reading on implementation strategies, see the Wikipedia overview of Assertions<\/a>.<\/p>assert.h<\/code> header provides a macro to check expressions at runtime. In JAVA<\/a>, the assert<\/code> keyword was introduced to facilitate internal testing, as detailed in the Oracle Java Documentation<\/a>. Similarly, PYTHON<\/a> utilizes an assert<\/code> statement for internal consistency checks; however, as noted in the Python Software Foundation<\/a> documentation, these can be optimized away when the interpreter is run with optimization flags.<\/p>