Fix Android Vietnamese IME input (#1032)

src/ui/features/terminal/android-ime.test.ts

@@ -0,0 +1,48 @@
+import { afterEach, describe, expect, it } from "vitest";
+import { Terminal } from "@xterm/xterm";
+
+const tick = () => new Promise((resolve) => setTimeout(resolve, 0));
+
+describe("Android IME composition", () => {
+  let terminal: Terminal | undefined;
+  let container: HTMLDivElement | undefined;
+
+  afterEach(() => {
+    terminal?.dispose();
+    container?.remove();
+    terminal = undefined;
+    container = undefined;
+  });
+
+  it("forwards a shorter Vietnamese replacement to the shell", async () => {
+    container = document.createElement("div");
+    document.body.appendChild(container);
+    terminal = new Terminal();
+    terminal.open(container);
+
+    const input: string[] = [];
+    terminal.onData((data) => input.push(data));
+
+    const textarea = terminal.textarea!;
+    textarea.value = "Hoar";
+    textarea.selectionStart = textarea.value.length;
+    textarea.selectionEnd = textarea.value.length;
+    textarea.dispatchEvent(new CompositionEvent("compositionstart"));
+    textarea.dispatchEvent(
+      new CompositionEvent("compositionupdate", { data: "Hoar" }),
+    );
+    await tick();
+
+    textarea.value = "Hỏa";
+    textarea.selectionStart = textarea.value.length;
+    textarea.selectionEnd = textarea.value.length;
+    textarea.dispatchEvent(
+      new CompositionEvent("compositionupdate", { data: "Hỏa" }),
+    );
+    await tick();
+    textarea.dispatchEvent(new CompositionEvent("compositionend"));
+    await tick();
+
+    expect(input.join("")).toBe("\x7f\x7f\x7fỏa");
+  });
+});