Steel thread

As explained in BDD in Action, Second Edition

A steel thread is a minimal, end-to-end implementation path that exercises the essential workflow of a system before broader functionality is developed.

A steel thread is the smallest set of end-to-end scenarios that lets an actor accomplish a goal. It keeps acceptance-test implementation focused on the critical workflow instead of expanding prematurely into every feature, usage scenario, and business rule. section 14.1.4

Treat “end to end” as workflow breadth rather than UI depth: exercise the path from beginning to end, while using APIs or in-memory databases where appropriate instead of requiring a fully deployed system. section 14.1.4

A booking workflow

Start with the narrowest scenario that takes an actor from user sign-up through sign-in, flight search, and booking. Extend that thread with further scenarios only after the essential path is exercised. section 14.1.4

Figure 14.7 Establishing a steel thread of simplest possible scenarios required to accomplish a given goal

Shows the steel thread as the simplest connected path across the scenarios required to accomplish a goal. section 14.1.4

How BDD in Action, Second Edition covers it

How deep it goes

Defines the technique and clarifies workflow breadth, but stops short of prescribing detailed scenario-selection steps.

Examples

Uses sign-up, sign-in, flight search, and booking as a connected workflow example.

What it assumes

Assumes an existing system, a defined actor goal, and acceptance-test work spanning features, workflows, and business rules.

What you can do after

Apply it via a minimal automated workflow that tests the actor’s goal and checks the overall system understanding.

How it connects

Connects acceptance testing with end-to-end testing, software architecture, APIs, and in-memory databases.

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Related concepts

• feature mappingused by · Feature mapping is a collaborative requirements technique for exploring and organizing a software feature's behavior, flows, variations, and examples.
• feedbackproduces · Feedback is information about an action, system, or outcome that can inform evaluation, decisions, or subsequent behavior.
• end-to-end testinguses · End-to-end testing evaluates a complete system workflow across integrated components, from an external or user-relevant input to an observable outcome.

This explainer was generated by Manning's knowledge graph from the text of BDD in Action, Second Edition. The section links point to the parts of the book it draws on.