test: METHOD_IMPLEMENTS integration tests for C#, TypeScript, Kotlin, Dart

Add interface dispatch fixtures and METHOD_IMPLEMENTS edge assertions for
the 4 remaining languages that support interfaces:

- C#: IRepository interface with Find/Save, SqlRepository implements
- TypeScript: IRepository interface with find/save, SqlRepository implements
- Kotlin: Repository interface with find/save, SqlRepository implements
- Dart: abstract Repository with find/save, SqlRepository implements

Fix: Kotlin interfaces use class_declaration AST node type — added
keyword-based detection in findEnclosingClassInfo to correctly label
them as Interface (not Class), enabling METHOD_IMPLEMENTS edge emission.

Total METHOD_IMPLEMENTS integration coverage: 9 languages
(Java, PHP, Rust, Swift, Python, C#, TypeScript, Kotlin, Dart)

gitnexus/src/core/ingestion/utils/ast-helpers.ts

@@ -337,7 +337,17 @@ export const findEnclosingClassInfo = (
             c.type === 'constant',
         );
       if (nameNode) {
-        const label = CONTAINER_TYPE_TO_LABEL[current.type] || 'Class';
+        let label = CONTAINER_TYPE_TO_LABEL[current.type] || 'Class';
+        // Kotlin: class_declaration with an anonymous "interface" keyword child
+        // is actually an interface, not a class. Refine the label to match the
+        // node ID generated from the tree-sitter query capture (@definition.interface).
+        if (
+          current.type === 'class_declaration' &&
+          label === 'Class' &&
+          current.children?.some((c: SyntaxNode) => c.type === 'interface')
+        ) {
+          label = 'Interface';
+        }
         return {
           classId: generateId(label, `${filePath}:${nameNode.text}`),
           className: nameNode.text,

gitnexus/test/fixtures/lang-resolution/csharp-interface-dispatch/App.cs

@@ -0,0 +1,7 @@
+public class App {
+    public static void Main() {
+        IRepository repo = new SqlRepository();
+        repo.Find(1);
+        repo.Save("test");
+    }
+}

gitnexus/test/fixtures/lang-resolution/csharp-interface-dispatch/IRepository.cs

@@ -0,0 +1,4 @@
+public interface IRepository {
+    string Find(int id);
+    bool Save(string entity);
+}

gitnexus/test/fixtures/lang-resolution/csharp-interface-dispatch/SqlRepository.cs

@@ -0,0 +1,9 @@
+public class SqlRepository : IRepository {
+    public string Find(int id) {
+        return "found";
+    }
+
+    public bool Save(string entity) {
+        return true;
+    }
+}

gitnexus/test/fixtures/lang-resolution/dart-interface-dispatch/app.dart

@@ -0,0 +1,7 @@
+import 'sql_repository.dart';
+
+void main() {
+  final repo = SqlRepository();
+  repo.find(1);
+  repo.save("test");
+}

gitnexus/test/fixtures/lang-resolution/dart-interface-dispatch/repository.dart

@@ -0,0 +1,4 @@
+abstract class Repository {
+  String find(int id);
+  bool save(String entity);
+}

gitnexus/test/fixtures/lang-resolution/dart-interface-dispatch/sql_repository.dart

@@ -0,0 +1,13 @@
+import 'repository.dart';
+
+class SqlRepository implements Repository {
+  @override
+  String find(int id) {
+    return "found";
+  }
+
+  @override
+  bool save(String entity) {
+    return true;
+  }
+}

gitnexus/test/fixtures/lang-resolution/kotlin-interface-dispatch/App.kt

@@ -0,0 +1,5 @@
+fun main() {
+    val repo: Repository = SqlRepository()
+    repo.find(1)
+    repo.save("test")
+}

gitnexus/test/fixtures/lang-resolution/kotlin-interface-dispatch/Repository.kt

@@ -0,0 +1,4 @@
+interface Repository {
+    fun find(id: Int): String
+    fun save(entity: String): Boolean
+}

gitnexus/test/fixtures/lang-resolution/kotlin-interface-dispatch/SqlRepository.kt

@@ -0,0 +1,9 @@
+class SqlRepository : Repository {
+    override fun find(id: Int): String {
+        return "found"
+    }
+
+    override fun save(entity: String): Boolean {
+        return true
+    }
+}

gitnexus/test/fixtures/lang-resolution/typescript-interface-dispatch/app.ts

@@ -0,0 +1,5 @@
+import { SqlRepository } from './sql-repository';
+
+const repo = new SqlRepository();
+repo.find(1);
+repo.save("test");

gitnexus/test/fixtures/lang-resolution/typescript-interface-dispatch/repository.ts

@@ -0,0 +1,4 @@
+export interface IRepository {
+    find(id: number): string;
+    save(entity: string): boolean;
+}

gitnexus/test/fixtures/lang-resolution/typescript-interface-dispatch/sql-repository.ts

@@ -0,0 +1,11 @@
+import { IRepository } from './repository';
+
+export class SqlRepository implements IRepository {
+    find(id: number): string {
+        return "found";
+    }
+
+    save(entity: string): boolean {
+        return true;
+    }
+}

gitnexus/test/integration/resolvers/csharp.test.ts

@@ -1722,3 +1722,48 @@ describe('C# method enrichment', () => {
     expect(classifyCall).toBeDefined();
   });
 });
+
+// ---------------------------------------------------------------------------
+// Interface dispatch: METHOD_IMPLEMENTS edges
+// ---------------------------------------------------------------------------
+
+describe('C# interface dispatch (METHOD_IMPLEMENTS)', () => {
+  let result: PipelineResult;
+
+  beforeAll(async () => {
+    result = await runPipelineFromRepo(path.join(FIXTURES, 'csharp-interface-dispatch'), () => {});
+  }, 60000);
+
+  it('detects IRepository interface and SqlRepository class', () => {
+    const classes = getNodesByLabel(result, 'Class');
+    const ifaces = getNodesByLabel(result, 'Interface');
+    expect(classes).toContain('SqlRepository');
+    expect(ifaces).toContain('IRepository');
+  });
+
+  it('emits IMPLEMENTS edge SqlRepository → IRepository', () => {
+    const impl = getRelationships(result, 'IMPLEMENTS');
+    const edge = impl.find((e) => e.source === 'SqlRepository' && e.target === 'IRepository');
+    expect(edge).toBeDefined();
+  });
+
+  it('emits METHOD_IMPLEMENTS edges for Find and Save', () => {
+    const mi = getRelationships(result, 'METHOD_IMPLEMENTS');
+    const findEdge = mi.find(
+      (e) =>
+        e.source === 'Find' &&
+        e.target === 'Find' &&
+        e.sourceFilePath.includes('SqlRepository') &&
+        e.targetFilePath.includes('IRepository'),
+    );
+    const saveEdge = mi.find(
+      (e) =>
+        e.source === 'Save' &&
+        e.target === 'Save' &&
+        e.sourceFilePath.includes('SqlRepository') &&
+        e.targetFilePath.includes('IRepository'),
+    );
+    expect(findEdge).toBeDefined();
+    expect(saveEdge).toBeDefined();
+  });
+});

gitnexus/test/integration/resolvers/dart.test.ts

@@ -429,3 +429,48 @@ describe.skipIf(!dartAvailable)('Dart async method detection', () => {
     expect(formatName!.properties.returnType).toBe('String');
   });
 });
+
+// ---------------------------------------------------------------------------
+// Interface dispatch: METHOD_IMPLEMENTS edges from concrete → abstract methods
+// abstract Repository with find/save, SqlRepository implements them
+// ---------------------------------------------------------------------------
+
+describe.skipIf(!dartAvailable)('Dart interface dispatch (METHOD_IMPLEMENTS)', () => {
+  let result: PipelineResult;
+
+  beforeAll(async () => {
+    result = await runPipelineFromRepo(path.join(FIXTURES, 'dart-interface-dispatch'), () => {});
+  }, 60000);
+
+  it('detects Repository class and SqlRepository class', () => {
+    const classes = getNodesByLabel(result, 'Class');
+    expect(classes).toContain('Repository');
+    expect(classes).toContain('SqlRepository');
+  });
+
+  it('emits IMPLEMENTS edge SqlRepository → Repository', () => {
+    const impl = getRelationships(result, 'IMPLEMENTS');
+    const edge = impl.find((e) => e.source === 'SqlRepository' && e.target === 'Repository');
+    expect(edge).toBeDefined();
+  });
+
+  it('emits METHOD_IMPLEMENTS edges for find and save', () => {
+    const mi = getRelationships(result, 'METHOD_IMPLEMENTS');
+    const findEdge = mi.find(
+      (e) =>
+        e.source === 'find' &&
+        e.target === 'find' &&
+        e.sourceFilePath.includes('sql_repository') &&
+        e.targetFilePath.includes('repository'),
+    );
+    const saveEdge = mi.find(
+      (e) =>
+        e.source === 'save' &&
+        e.target === 'save' &&
+        e.sourceFilePath.includes('sql_repository') &&
+        e.targetFilePath.includes('repository'),
+    );
+    expect(findEdge).toBeDefined();
+    expect(saveEdge).toBeDefined();
+  });
+});

gitnexus/test/integration/resolvers/kotlin.test.ts

@@ -1811,3 +1811,49 @@ describe('Kotlin method enrichment', () => {
     expect(classifyCall).toBeDefined();
   });
 });
+
+// ---------------------------------------------------------------------------
+// Interface dispatch: METHOD_IMPLEMENTS edges from concrete → interface methods
+// Repository interface with find/save, SqlRepository implements them
+// ---------------------------------------------------------------------------
+
+describe('Kotlin interface dispatch (METHOD_IMPLEMENTS)', () => {
+  let result: PipelineResult;
+
+  beforeAll(async () => {
+    result = await runPipelineFromRepo(path.join(FIXTURES, 'kotlin-interface-dispatch'), () => {});
+  }, 60000);
+
+  it('detects Repository interface and SqlRepository class', () => {
+    const classes = getNodesByLabel(result, 'Class');
+    const ifaces = getNodesByLabel(result, 'Interface');
+    expect(classes).toContain('SqlRepository');
+    expect(ifaces).toContain('Repository');
+  });
+
+  it('emits IMPLEMENTS edge SqlRepository → Repository', () => {
+    const impl = getRelationships(result, 'IMPLEMENTS');
+    const edge = impl.find((e) => e.source === 'SqlRepository' && e.target === 'Repository');
+    expect(edge).toBeDefined();
+  });
+
+  it('emits METHOD_IMPLEMENTS edges for find and save', () => {
+    const mi = getRelationships(result, 'METHOD_IMPLEMENTS');
+    const findEdge = mi.find(
+      (e) =>
+        e.source === 'find' &&
+        e.target === 'find' &&
+        e.sourceFilePath.includes('SqlRepository') &&
+        e.targetFilePath.includes('Repository'),
+    );
+    const saveEdge = mi.find(
+      (e) =>
+        e.source === 'save' &&
+        e.target === 'save' &&
+        e.sourceFilePath.includes('SqlRepository') &&
+        e.targetFilePath.includes('Repository'),
+    );
+    expect(findEdge).toBeDefined();
+    expect(saveEdge).toBeDefined();
+  });
+});

gitnexus/test/integration/resolvers/typescript.test.ts

@@ -2395,3 +2395,51 @@ describe('TypeScript method enrichment', () => {
     expect(classifyCall).toBeDefined();
   });
 });
+
+// ---------------------------------------------------------------------------
+// Interface dispatch: METHOD_IMPLEMENTS edges
+// ---------------------------------------------------------------------------
+
+describe('TypeScript interface dispatch (METHOD_IMPLEMENTS)', () => {
+  let result: PipelineResult;
+
+  beforeAll(async () => {
+    result = await runPipelineFromRepo(
+      path.join(FIXTURES, 'typescript-interface-dispatch'),
+      () => {},
+    );
+  }, 60000);
+
+  it('detects IRepository interface and SqlRepository class', () => {
+    const classes = getNodesByLabel(result, 'Class');
+    const ifaces = getNodesByLabel(result, 'Interface');
+    expect(classes).toContain('SqlRepository');
+    expect(ifaces).toContain('IRepository');
+  });
+
+  it('emits IMPLEMENTS edge SqlRepository → IRepository', () => {
+    const impl = getRelationships(result, 'IMPLEMENTS');
+    const edge = impl.find((e) => e.source === 'SqlRepository' && e.target === 'IRepository');
+    expect(edge).toBeDefined();
+  });
+
+  it('emits METHOD_IMPLEMENTS edges for find and save', () => {
+    const mi = getRelationships(result, 'METHOD_IMPLEMENTS');
+    const findEdge = mi.find(
+      (e) =>
+        e.source === 'find' &&
+        e.target === 'find' &&
+        e.sourceFilePath.includes('sql-repository') &&
+        e.targetFilePath.includes('repository'),
+    );
+    const saveEdge = mi.find(
+      (e) =>
+        e.source === 'save' &&
+        e.target === 'save' &&
+        e.sourceFilePath.includes('sql-repository') &&
+        e.targetFilePath.includes('repository'),
+    );
+    expect(findEdge).toBeDefined();
+    expect(saveEdge).toBeDefined();
+  });
+});