In the context of software or information modeling, a happy path (sometimes called happy flow) is a default
scenario
In the performing arts, a scenario (, ; ; ) is a synoptical collage of an event or series of actions and events. In the ''commedia dell'arte'', it was an outline of entrances, exits, and action describing the plot of a play, and was literally pi ...
featuring no
exceptional or error conditions.
For example, the happy path for a function validating credit card numbers would be where none of the
validation rule
In computer science, data validation is the process of ensuring data has undergone data cleansing to ensure they have data quality, that is, that they are both correct and useful. It uses routines, often called "validation rules", "validation con ...
s raise an error, thus letting execution continue successfully to the end, generating a positive response.
Process steps for a happy path are also used in the context of a
use case
In software and systems engineering, the phrase use case is a polyseme with two senses:
# A usage scenario for a piece of software; often used in the plural to suggest situations where a piece of software may be useful.
# A potential scenario ...
. In contrast to the happy path, process steps for alternate paths and exception paths may also be documented.
Happy path test is a well-defined
test case
In software engineering, a test case is a specification of the inputs, execution conditions, testing procedure, and expected results that define a single test to be executed to achieve a particular software testing objective, such as to exercise ...
using known input, which executes without exception and produces an expected output.
Happy path testing can show that a system meets its
functional requirements
In software engineering and systems engineering, a functional requirement defines a function of a system or its component, where a function is described as a specification of behavior between inputs and outputs.
Functional requirements may invol ...
but it doesn't guarantee a graceful handling of error conditions or aid in finding hidden
bugs.
Happy day (or sunny day) scenario and golden path are synonyms for happy path.
In use case analysis, there is only one happy path, but there may be any number of additional alternate path scenarios which are all valid optional outcomes. If valid alternatives exist, the happy path is then identified as the default or most likely positive alternative. The analysis may also show one or more exception paths. An exception path is taken as the result of a fault condition. Use cases and the resulting interactions are commonly modeled in graphical languages such as the
Unified Modeling Language
The Unified Modeling Language (UML) is a general-purpose, developmental modeling language in the field of software engineering that is intended to provide a standard way to visualize the design of a system.
The creation of UML was originally m ...
(UML) or
SysML
The Systems Modeling Language (SysML) is a general-purpose modeling language for systems engineering applications. It supports the specification, analysis, design, verification and validation of a broad range of systems and systems-of-systems.
S ...
.
Unhappy path
There is no agreed name for the opposite of happy paths: they may be known as sad paths, bad paths, or exception paths. The term 'unhappy path' is gaining popularity as it suggests a complete opposite to 'happy path' and retains the same context. Usually there is no extra 'unhappy path', leaving such 'term' meaningless, because the happy path reaches the utter end, but an 'unhappy path' is shorter, ends prematurely, and doesn't reach the desired end, i.e. not even the last page of a wizard. And in contrast to a single happy path, there are a lot of different ways in which things can go wrong, so there is no single criterion to determine 'the unhappy path'.
See also
*
Edge case
An edge case is a problem or situation that occurs only at an extreme (maximum or minimum) operating parameter. For example, a stereo speaker might noticeably distort audio when played at maximum volume, even in the absence of any other extreme ...
*
Corner case
In engineering, a corner case (or pathological case) involves a problem or situation that occurs only outside normal operating parameters—specifically one that manifests itself when multiple environmental variables or conditions are simultaneou ...
*
Use case
In software and systems engineering, the phrase use case is a polyseme with two senses:
# A usage scenario for a piece of software; often used in the plural to suggest situations where a piece of software may be useful.
# A potential scenario ...
References
Computer programming
Software testing
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