test: add multiline prompt completion regression for readline

Author: Han5991

test/parallel/test-readline-tab-complete.js

@@ -138,3 +138,172 @@ if (process.env.TERM === 'dumb') {
     }));
   }));
 }
+
+{
+	class VirtualScreen {
+		constructor() {
+			this.rows = [[]];
+			this.row = 0;
+			this.col = 0;
+		}
+
+		ensureRow(row) {
+			while (this.rows.length <= row) this.rows.push([]);
+		}
+
+		setChar(row, col, ch) {
+			this.ensureRow(row);
+			const target = this.rows[row];
+			while (target.length <= col) target.push(' ');
+			target[col] = ch;
+		}
+
+		clearLineRight() {
+			this.ensureRow(this.row);
+			const target = this.rows[this.row];
+			if (this.col < target.length) {
+				target.length = this.col;
+			}
+		}
+
+		clearFromCursor() {
+			this.clearLineRight();
+			if (this.row + 1 < this.rows.length) {
+				this.rows.length = this.row + 1;
+			}
+		}
+
+		moveCursor(dx, dy) {
+			this.row = Math.max(0, this.row + dy);
+			this.ensureRow(this.row);
+			this.col = Math.max(0, this.col + dx);
+		}
+
+		handleEscape(params, code) {
+			switch (code) {
+				case 'A': // Cursor Up
+					this.moveCursor(0, -(Number(params) || 1));
+					break;
+				case 'B': // Cursor Down
+					this.moveCursor(0, Number(params) || 1);
+					break;
+				case 'C': // Cursor Forward
+					this.moveCursor(Number(params) || 1, 0);
+					break;
+				case 'D': // Cursor Backward
+					this.moveCursor(-(Number(params) || 1), 0);
+					break;
+				case 'G': // Cursor Horizontal Absolute
+					this.col = Math.max(0, (Number(params) || 1) - 1);
+					break;
+				case 'H':
+				case 'f': { // Cursor Position
+					const [row, col] = params.split(';').map((n) => Number(n) || 1);
+					this.row = Math.max(0, row - 1);
+					this.col = Math.max(0, (col ?? 1) - 1);
+					this.ensureRow(this.row);
+					break;
+				}
+				case 'J':
+					this.clearFromCursor();
+					break;
+				case 'K':
+					this.clearLineRight();
+					break;
+				default:
+					break;
+			}
+		}
+
+		write(chunk) {
+			for (let i = 0; i < chunk.length; i++) {
+				const ch = chunk[i];
+				if (ch === '\r') {
+					this.col = 0;
+					continue;
+				}
+				if (ch === '\n') {
+					this.row++;
+					this.col = 0;
+					this.ensureRow(this.row);
+					continue;
+				}
+				if (ch === '\u001b' && chunk[i + 1] === '[') {
+					const match = /^\u001b\[([0-9;]*)([A-Za-z])/.exec(chunk.slice(i));
+					if (match) {
+						this.handleEscape(match[1], match[2]);
+						i += match[0].length - 1;
+						continue;
+					}
+				}
+				this.setChar(this.row, this.col, ch);
+				this.col++;
+			}
+		}
+
+		getLines() {
+			return this.rows.map((row) => row.join('').trimEnd());
+		}
+	}
+
+	class FakeTTY extends EventEmitter {
+		columns = 80;
+		rows = 24;
+		isTTY = true;
+
+		constructor(screen) {
+			super();
+			this.screen = screen;
+		}
+
+		write(data) {
+			this.screen.write(data);
+			return true;
+		}
+
+		resume() {}
+
+		pause() {}
+
+		end() {}
+
+		setRawMode(mode) {
+			this.isRaw = mode;
+		}
+	}
+
+	const screen = new VirtualScreen();
+	const fi = new FakeTTY(screen);
+
+	const rli = new readline.Interface({
+		input: fi,
+		output: fi,
+		terminal: true,
+		completer: (line) => [['foobar', 'foobaz'], line],
+	});
+
+	const promptLines = ['multiline', 'prompt', 'eats', 'output', '> '];
+	rli.setPrompt(promptLines.join('\n'));
+	rli.prompt();
+
+	['f', 'o', 'o', '\t', '\t'].forEach((ch) => fi.emit('data', ch));
+
+	const display = screen.getLines();
+
+	assert.strictEqual(display[0], 'multiline');
+	assert.strictEqual(display[1], 'prompt');
+	assert.strictEqual(display[2], 'eats');
+	assert.strictEqual(display[3], 'output');
+
+	const inputLineIndex = 4;
+	assert.ok(
+		display[inputLineIndex].includes('> fooba'),
+		'prompt line should keep completed input',
+	);
+
+	const completionLineExists =
+		display.some((l) => l.includes('foobar') && l.includes('foobaz'));
+	assert.ok(completionLineExists, 'completion list should be visible');
+
+	rli.close();
+}