feat: tab completions for file paths (#279)

Made a PR as was requested in the #113

codex-cli/tests/terminal-chat-completions.test.tsx

@@ -0,0 +1,46 @@
+import React from "react";
+import { describe, it, expect } from "vitest";
+import type { ComponentProps } from "react";
+import { renderTui } from "./ui-test-helpers.js";
+import TerminalChatCompletions from "../src/components/chat/terminal-chat-completions.js";
+
+describe("TerminalChatCompletions", () => {
+  const baseProps: ComponentProps<typeof TerminalChatCompletions> = {
+    completions: ["Option 1", "Option 2", "Option 3", "Option 4", "Option 5"],
+    displayLimit: 3,
+    selectedCompletion: 0,
+  };
+
+  it("renders visible completions within displayLimit", async () => {
+    const { lastFrameStripped } = renderTui(
+      <TerminalChatCompletions {...baseProps} />,
+    );
+    const frame = lastFrameStripped();
+    expect(frame).toContain("Option 1");
+    expect(frame).toContain("Option 2");
+    expect(frame).toContain("Option 3");
+    expect(frame).not.toContain("Option 4");
+  });
+
+  it("centers the selected completion in the visible list", async () => {
+    const { lastFrameStripped } = renderTui(
+      <TerminalChatCompletions {...baseProps} selectedCompletion={2} />,
+    );
+    const frame = lastFrameStripped();
+    expect(frame).toContain("Option 2");
+    expect(frame).toContain("Option 3");
+    expect(frame).toContain("Option 4");
+    expect(frame).not.toContain("Option 1");
+  });
+
+  it("adjusts when selectedCompletion is near the end", async () => {
+    const { lastFrameStripped } = renderTui(
+      <TerminalChatCompletions {...baseProps} selectedCompletion={4} />,
+    );
+    const frame = lastFrameStripped();
+    expect(frame).toContain("Option 3");
+    expect(frame).toContain("Option 4");
+    expect(frame).toContain("Option 5");
+    expect(frame).not.toContain("Option 2");
+  });
+});