add missing unit test suite

tests/compose-docker-args.test.ts

@@ -0,0 +1,49 @@
+/**
+ * #1393: the compose daemon must be passed on the `docker -H` flag, never as
+ * DOCKER_HOST in the shell env (which leaks into services that pass through or
+ * interpolate DOCKER_HOST). These are the pure resolver + argv builder.
+ */
+import { describe, test, expect } from 'bun:test';
+import {
+	resolveComposeDockerHost,
+	buildComposeBaseArgs
+} from '../src/lib/server/compose-docker-args';
+
+describe('resolveComposeDockerHost', () => {
+	test('per-env dockerHost wins', () => {
+		expect(resolveComposeDockerHost('tcp://remote:2375', 'unix:///own.sock')).toBe('tcp://remote:2375');
+	});
+	test("falls back to Dockhand's own DOCKER_HOST (socket-proxy setup)", () => {
+		expect(resolveComposeDockerHost(undefined, 'tcp://dockhand-socket-proxy:2375')).toBe(
+			'tcp://dockhand-socket-proxy:2375'
+		);
+	});
+	test('undefined for a plain local socket (no host anywhere)', () => {
+		expect(resolveComposeDockerHost(undefined, undefined)).toBeUndefined();
+		expect(resolveComposeDockerHost(null, null)).toBeUndefined();
+		expect(resolveComposeDockerHost('', '')).toBeUndefined();
+	});
+});
+
+describe('buildComposeBaseArgs', () => {
+	test('puts the daemon on -H BEFORE compose (global docker flag)', () => {
+		expect(buildComposeBaseArgs('mystack', 'tcp://remote:2375')).toEqual([
+			'docker',
+			'-H',
+			'tcp://remote:2375',
+			'compose',
+			'-p',
+			'mystack'
+		]);
+	});
+	test('omits -H entirely when there is no host (default local socket)', () => {
+		const args = buildComposeBaseArgs('mystack', undefined);
+		expect(args).toEqual(['docker', 'compose', '-p', 'mystack']);
+		// crucially, DOCKER_HOST / -H never appears
+		expect(args).not.toContain('-H');
+	});
+	test('the daemon is NEVER placed after `compose` (would be an invalid subcommand flag)', () => {
+		const args = buildComposeBaseArgs('s', 'unix:///own.sock');
+		expect(args.indexOf('-H')).toBeLessThan(args.indexOf('compose'));
+	});
+});