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name: ui5-best-practices-qunit description: | Use when the user asks to "write a QUnit test", "fix a failing QUnit test", "add a QUnit module", "modernize QUnit tests", "migrate from QUnit 1", or mentions QUnit-specific constructs such as assert.async, nextUIUpdate, Core.applyChanges, sinon sandbox, asyncTest, or QUnit.module. Covers coding standards for OpenUI5/SAPUI5 unit test files: const/let over var, arrow functions over .bind(this), async/await over assert.async(), assert.expect() in every async test, sinon.createSandbox(), descriptive test names, beforeEach/afterEach module isolation, nextUIUpdate vs Core.applyChanges rules, try/finally teardown in helpers, QUnit 1 to QUnit 2 globals migration, and non-ASCII character avoidance.

QUnit Test Best Practices for UI5

When to load each reference

Trigger	Load
Writing a new QUnit test file or module from scratch	references/writing-new-tests.md
Modernizing, refactoring, or reviewing existing test code	references/modernizing-tests.md
Migrating from QUnit 1 (globals: test, asyncTest, ok, stop, start) to QUnit 2	references/modernizing-tests.md
Any test touches nextUIUpdate, Core.applyChanges, assert.async, fake timers, or event-based async	references/async-patterns.md

Load the reference before producing any output. Do not work from memory.

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Core rules (always apply)

Rule	Detail
No var	Use const or let. One declaration per line - no comma chains.
No .bind(this)	Use arrow functions for callbacks that do not need their own this.
assert.expect(N) in every async test	Guards against silent passes when async callbacks never fire. Not required for sync tests.
sinon.createSandbox()	sinon.sandbox.create() emits a runtime deprecation warning in Sinon 5+ - prefer sinon.createSandbox(). Alternatively use the QUnit-sinon bridge (this.stub(), this.spy(), this.mock(); this.clock only when sinon.config.useFakeTimers is truthy). Do not mix both approaches in the same module.
Descriptive test names	Sentence describing behavior. Never start with "it should". Unique within each module.
beforeEach / afterEach in every module	Create all controls in beforeEach, destroy them in afterEach. No shared mutable state between tests.
try/finally in helper-created controls	Helpers that create a control must destroy it in finally so it is cleaned up even when assertions throw.
No non-ASCII characters	No non-ASCII characters in comments, strings, or JSDoc. Use plain ASCII hyphens, not em dashes. UTF-8 is required, but non-ASCII in comments has historically caused encoding issues.
ESLint - 0 errors	Warnings for pre-existing patterns (max-nested-callbacks, no-use-before-define, valid-jsdoc) are acceptable.

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Quick-reference checklist

Use when authoring or reviewing a QUnit test file:

• No var - use const or let; one declaration per line (no comma chains)
• No .bind(this) - use arrow functions for callbacks that do not need their own this
• No assert.async() in simple cases - use async function + await new Promise(...)
• Every async test has assert.expect(N)
• No sinon.sandbox.create() in new code - use sinon.createSandbox() or the bridge (this.stub(), this.spy(), this.mock()); this.clock only when fake timers are enabled
• No "it should..." test titles - use descriptive sentences
• Every QUnit.module has beforeEach / afterEach that create and destroy all controls
• With fake timers: prefer await nextUIUpdate(this.clock) over Core.applyChanges(); only keep Core.applyChanges() when nextUIUpdate(clock) cannot handle the case
• Helper functions that create controls destroy them in try/finally
• No non-ASCII characters in comments or strings (UTF-8 required, but non-ASCII causes encoding issues)