Errors, debugging, and testing definitions

Error

An error is a problem or mistake in a program, its logic, or its input that leads to incorrect behaviour that ultimately leads to a test of the function being unable to execute due to an unexpected issue.

Failure

A failure is when a program does not behave as expected, in testing, this means that the test runs successfully but an assertation does not pass.

Exception

An exception is an error detected during program execution that interrupts normal flow unless handled. Usually these come in the form of invalid inputs.

TypeError

A TypeError occurs when an operation or function is used with an object of an inappropriate type.

ValueError

A ValueError occurs when the type of a value is correct but the value itself is inappropriate.

KeyError

A KeyError occurs when the code tries to access a dictionary key that does not exist and no fallback is provided.

Stack trace

A stack trace is the error output that shows where an exception occurred in the program.

Debugging

Debugging is the process of finding and fixing errors in code.

Linting

Linting is the process of automatically checking source code for problems such as style issues, suspicious patterns, and possible errors. A linter can flag a functions for not following PEP8 naming style, point out unclear variable names, formatting issues in Python code.

Test

A test is a check used to see whether code behaves as expected for a given input.

Test case

A test case is a specific input together with the expected output or expected error.

Valid input

Valid input is input that matches the required type and structure for a function.

Invalid input

Invalid input is input that does not satisfy the requires type, format, or constraints of a function. An example of this would be passing a list instead of a dictionary.

Boundary case

A boundary case is a test case at the edge of a condition where behaviour may change.