test(scala): add integration test with multi-file fixture

3-file Scala fixture (User.scala, UserService.scala, Main.scala)
exercising: file detection, class/trait/object extraction, method
extraction, call edges, and cross-file resolution.

gitnexus/test/fixtures/lang-resolution/scala-app/Main.scala

@@ -0,0 +1,8 @@
+import services.UserService
+
+object Main {
+  def main(args: Array[String]): Unit = {
+    val user = UserService.createUser("Alice", "alice@example.com")
+    UserService.process(user)
+  }
+}

gitnexus/test/fixtures/lang-resolution/scala-app/models/User.scala

@@ -0,0 +1,15 @@
+package models
+
+trait Greeter {
+  def greet(name: String): String
+}
+
+class User(val name: String, val email: String) extends Greeter {
+  def greet(name: String): String = s"Hello, $name"
+
+  def getEmail: String = email
+}
+
+object User {
+  def create(name: String, email: String): User = new User(name, email)
+}

gitnexus/test/fixtures/lang-resolution/scala-app/services/UserService.scala

@@ -0,0 +1,14 @@
+package services
+
+import models.User
+
+object UserService {
+  def createUser(name: String, email: String): User = {
+    User.create(name, email)
+  }
+
+  def process(user: User): Unit = {
+    val greeting = user.greet(user.name)
+    println(greeting)
+  }
+}

gitnexus/test/integration/resolvers/scala.test.ts

@@ -0,0 +1,66 @@
+/**
+ * Scala: basic pipeline integration — classes, traits, objects, methods, imports, calls.
+ * Verifies that the Scala language provider correctly parses JVM-style code
+ * with class/trait/object definitions, method extraction, and cross-file calls.
+ */
+import { describe, it, expect, beforeAll } from 'vitest';
+import path from 'path';
+import {
+  FIXTURES,
+  getRelationships,
+  getNodesByLabel,
+  runPipelineFromRepo,
+  type PipelineResult,
+} from './helpers.js';
+import { isLanguageAvailable } from '../../../src/core/tree-sitter/parser-loader.js';
+import { SupportedLanguages } from '../../../src/config/supported-languages.js';
+
+const scalaAvailable = isLanguageAvailable(SupportedLanguages.Scala);
+
+describe.skipIf(!scalaAvailable)('Scala pipeline integration', () => {
+  let result: PipelineResult;
+
+  beforeAll(async () => {
+    result = await runPipelineFromRepo(path.join(FIXTURES, 'scala-app'), () => {});
+  }, 60000);
+
+  it('detects Scala files', () => {
+    const files = getNodesByLabel(result, 'File');
+    expect(files).toContain('Main.scala');
+    expect(files).toContain('User.scala');
+    expect(files).toContain('UserService.scala');
+  });
+
+  it('extracts classes, traits, and objects', () => {
+    const classes = getNodesByLabel(result, 'Class');
+    const interfaces = getNodesByLabel(result, 'Interface');
+    expect(classes).toContain('User');
+    expect(classes).toContain('UserService');
+    expect(classes).toContain('Main');
+    expect(interfaces).toContain('Greeter');
+  });
+
+  it('extracts methods', () => {
+    const methods = getNodesByLabel(result, 'Method');
+    expect(methods).toContain('greet');
+    expect(methods).toContain('getEmail');
+    expect(methods).toContain('create');
+    expect(methods).toContain('createUser');
+    expect(methods).toContain('process');
+    expect(methods).toContain('main');
+  });
+
+  it('extracts call edges', () => {
+    const calls = getRelationships(result, 'CALLS');
+    expect(calls.length).toBeGreaterThanOrEqual(1);
+    const callNames = calls.map((c) => c.target);
+    expect(callNames).toContain('create');
+  });
+
+  it('extracts cross-file calls', () => {
+    const calls = getRelationships(result, 'CALLS');
+    const callNames = calls.map((c) => c.target);
+    expect(callNames).toContain('createUser');
+    expect(callNames).toContain('process');
+  });
+});