Open OAuth login URLs during setup

tests/open-url.test.ts

@@ -0,0 +1,45 @@
+import test from "node:test";
+import assert from "node:assert/strict";
+
+import { getOpenUrlCommand } from "../src/system/open-url.js";
+
+test("getOpenUrlCommand uses open on macOS when available", () => {
+	const command = getOpenUrlCommand(
+		"https://example.com",
+		"darwin",
+		(name) => (name === "open" ? "/usr/bin/open" : undefined),
+	);
+
+	assert.deepEqual(command, {
+		command: "/usr/bin/open",
+		args: ["https://example.com"],
+	});
+});
+
+test("getOpenUrlCommand uses xdg-open on Linux when available", () => {
+	const command = getOpenUrlCommand(
+		"https://example.com",
+		"linux",
+		(name) => (name === "xdg-open" ? "/usr/bin/xdg-open" : undefined),
+	);
+
+	assert.deepEqual(command, {
+		command: "/usr/bin/xdg-open",
+		args: ["https://example.com"],
+	});
+});
+
+test("getOpenUrlCommand uses cmd start on Windows", () => {
+	const command = getOpenUrlCommand("https://example.com", "win32");
+
+	assert.deepEqual(command, {
+		command: "cmd",
+		args: ["/c", "start", "", "https://example.com"],
+	});
+});
+
+test("getOpenUrlCommand returns undefined when no opener is available", () => {
+	const command = getOpenUrlCommand("https://example.com", "linux", () => undefined);
+
+	assert.equal(command, undefined);
+});