Testing

@opentui/core/testing provides a renderer that does not write to the real terminal by default. It constructs CliRenderer directly with screenMode: "main-screen", consoleMode: "disabled", externalOutputMode: "passthrough", and native memory output.

import { createTestRenderer } from "@opentui/core/testing"
import { Text } from "@opentui/core"

const { renderer, renderOnce, captureCharFrame } = await createTestRenderer({ width: 40, height: 10 })

renderer.root.add(Text({ content: "Hello" }))
await renderOnce()

console.log(captureCharFrame())
renderer.destroy()

Helper	Description
`renderer`	The `CliRenderer` instance
`renderOnce()`	Run one render pass
`flush()`	Wait until scheduled rendering settles
`waitFor(predicate)`	Retry until a condition passes
`waitForFrame(predicate)`	Retry against captured frame text
`waitForVisualIdle()`	Wait for quiet native frames
`captureCharFrame()`	Read the current character frame as text
`captureSpans()`	Read styled span lines and cursor state
`externalOutput.takeText()`	Read captured split-footer output events
`getNativeStats()`	Read native render stats
`resize(width, height)`	Simulate a terminal resize
`mockInput` / `mockMouse`	Drive keyboard and mouse input

Use createCliRenderer() with custom stdin / stdout streams when a test needs the real output transport instead of memory output.