cucumber-tag-expressions

What is cucumber-tag-expressions?

The cucumber-tag-expressions npm package is used to evaluate tag expressions in Cucumber. It allows you to filter scenarios based on tags, enabling you to run specific subsets of tests. This is particularly useful for managing large test suites and running only relevant tests based on certain conditions.

What are cucumber-tag-expressions's main functionalities?

Parsing Tag Expressions

This feature allows you to parse tag expressions and evaluate them against a set of tags. The example demonstrates how to parse a complex tag expression and evaluate it against different sets of tags.

const TagExpressionParser = require('cucumber-tag-expressions').TagExpressionParser;
const parser = new TagExpressionParser();
const expressionNode = parser.parse('(@smoke or @regression) and not @wip');
console.log(expressionNode.evaluate(['@smoke'])); // true
console.log(expressionNode.evaluate(['@wip'])); // false

Combining Tag Expressions

This feature allows you to combine multiple tag expressions using logical operators like AND, OR, and NOT. The example shows how to combine two tag expressions and evaluate the combined expression.

const TagExpressionParser = require('cucumber-tag-expressions').TagExpressionParser;
const parser = new TagExpressionParser();
const expressionNode1 = parser.parse('@smoke');
const expressionNode2 = parser.parse('@regression');
const combinedExpression = expressionNode1.and(expressionNode2);
console.log(combinedExpression.evaluate(['@smoke', '@regression'])); // true
console.log(combinedExpression.evaluate(['@smoke'])); // false

Simplifying Tag Expressions

This feature allows you to simplify complex tag expressions. The example demonstrates how to parse a complex tag expression and then simplify it.

const TagExpressionParser = require('cucumber-tag-expressions').TagExpressionParser;
const parser = new TagExpressionParser();
const expressionNode = parser.parse('(@smoke or @regression) and not @wip');
const simplifiedExpression = expressionNode.simplify();
console.log(simplifiedExpression.toString()); // '(@smoke or @regression) and not @wip'

Other packages similar to cucumber-tag-expressions

cucumber

The cucumber package is a comprehensive tool for running Cucumber tests. It includes functionality for defining and running feature files, step definitions, and hooks. While it also supports tag expressions, it is a much larger package with a broader scope compared to cucumber-tag-expressions.

gherkin

The gherkin package is used for parsing Gherkin syntax, which is the language used for writing Cucumber feature files. It includes functionality for parsing feature files and extracting scenarios and steps. While it does not focus on tag expressions, it is often used in conjunction with Cucumber and related tools.

jest-cucumber

The jest-cucumber package integrates Cucumber-style testing with the Jest testing framework. It allows you to write feature files and step definitions using Jest. While it supports tagging scenarios, its primary focus is on integrating Cucumber with Jest rather than evaluating tag expressions.

README

Cucumber Tag Expressions for JavaScript

The docs are here.

Example

import {TagExpressionParser} from 'cucumber-tag-expressions'
const parser = new TagExpressionParser()

const expressionNode = parser.parse('@tagA and @tagB')

expressionNode.evaluate(["@tagA", "@tagB"]) // => true
expressionNode.evaluate(["@tagA", "@tagC"]) // => false