liquid-java · rcosta358 · Oct 2, 2026 · CatarinaGamboa · Oct 2, 2026
diff --git a/client/src/extension.ts b/client/src/extension.ts
@@ -12,12 +12,14 @@ import { registerAutocomplete } from "./services/autocomplete";
 import { refreshCodeLenses, registerCodeLens } from "./services/codelens";
 import { runLanguageServer, stopLanguageServer } from "./lsp/server";
 import { runClient, stopClient } from "./lsp/client";
+import type { LiquidJavaTestApi } from "./types/test-api";
 
 /**
  * Activates the LiquidJava extension
  * @param context The extension context
  */
-export async function activate(context: vscode.ExtensionContext) {
+export async function activate(context: vscode.ExtensionContext): Promise<LiquidJavaTestApi> {
+    context.subscriptions.push(extension.diagnosticsEmitter);
     registerLogger(context);
     extension.logger!.client.info("Activating LiquidJava extension...");
 
@@ -30,6 +32,22 @@ export async function activate(context: vscode.ExtensionContext) {
     registerHover();
     await applyItalicOverlay();
     await startExtension(context);
+
+    const ready = extension.client?.isRunning()
+        ? Promise.resolve()
+        : Promise.reject(new Error("LiquidJava language client did not start"));
+    // keep activation behavior while callers observe startup failures through ready
+    void ready.catch(() => {});
+
+    return {
+        ready,
+        onDiagnostics: extension.diagnosticsEmitter.event,
+        getState: () => ({
+            status: extension.status,
+            diagnostics: [...(extension.diagnostics ?? [])],
+        }),
+        onWebviewMessage: extension.webview!.onWebviewMessage,
+    };
 }
 
 /**

diff --git a/client/src/services/diagnostics.ts b/client/src/services/diagnostics.ts
@@ -19,6 +19,7 @@ export function handleLJDiagnostics(diagnostics: LJDiagnostic[]) {
     extension.webview?.sendMessage({ type: "diagnostics", diagnostics });
     if (extension.context)
         extension.webview?.sendMessage({ type: "context", context: extension.context, errorAtCursor: extension.errorAtCursor });
+    extension.diagnosticsEmitter.fire(diagnostics);
 }
 
 /**

diff --git a/client/src/services/webview.ts b/client/src/services/webview.ts
@@ -13,6 +13,7 @@ export function registerWebview(context: vscode.ExtensionContext) {
 
     // webview provider
     context.subscriptions.push(
+        extension.webview,
         vscode.window.registerWebviewViewProvider(LiquidJavaWebviewProvider.viewType, extension.webview)
     );
     // show view command

diff --git a/client/src/state.ts b/client/src/state.ts
@@ -25,6 +25,7 @@ export class ExtensionState {
     // application state
     file?: string;
     diagnostics?: LJDiagnostic[];
+    readonly diagnosticsEmitter = new vscode.EventEmitter<LJDiagnostic[]>();
     stateMachine?: LJStateMachine | null;
     context?: LJContext;
     currentSelection?: Range;

diff --git a/client/src/types/test-api.ts b/client/src/types/test-api.ts
@@ -0,0 +1,15 @@
+import type * as vscode from "vscode";
+import type { ExtensionStatus } from "../state";
+import type { LJDiagnostic } from "./diagnostics";
+
+export interface WebviewMessage {
+    direction: "toWebview" | "fromWebview";
+    message: any;
+}
+
+export interface LiquidJavaTestApi {
+    readonly ready: Promise<void>;
+    readonly onDiagnostics: vscode.Event<LJDiagnostic[]>;
+    getState(): { status: ExtensionStatus | undefined; diagnostics: LJDiagnostic[] };
+    readonly onWebviewMessage: vscode.Event<WebviewMessage>;
+}
diff --git a/client/src/webview/provider.ts b/client/src/webview/provider.ts
@@ -1,16 +1,19 @@
 import * as vscode from 'vscode';
 import { getHtml } from './html';
 import { highlightRange, openFile } from '../services/editor';
+import type { WebviewMessage } from '../types/test-api';
 
 /**
  * Webview provider for the LiquidJava extension
  * Provides an interactive user interface for the LiquidJava diagnostics 
  */
-export class LiquidJavaWebviewProvider implements vscode.WebviewViewProvider {
+export class LiquidJavaWebviewProvider implements vscode.WebviewViewProvider, vscode.Disposable {
   public static readonly viewType = "liquidJavaView";
   private view?: vscode.WebviewView;
   private messageEmitter = new vscode.EventEmitter<any>();
   public readonly onDidReceiveMessage = this.messageEmitter.event;
+  private webviewMessageEmitter = new vscode.EventEmitter<WebviewMessage>();
+  public readonly onWebviewMessage = this.webviewMessageEmitter.event;
 
   constructor(private readonly extensionUri: vscode.Uri) {}
 
@@ -29,6 +32,7 @@ export class LiquidJavaWebviewProvider implements vscode.WebviewViewProvider {
     // listen for messages coming from webview
     webviewView.webview.onDidReceiveMessage(message => {
       // emit the message to any external listeners
+      this.webviewMessageEmitter.fire({ direction: "fromWebview", message });
       this.messageEmitter.fire(message);
 
       // handle message
@@ -46,7 +50,14 @@ export class LiquidJavaWebviewProvider implements vscode.WebviewViewProvider {
    * @param message
    */
   public sendMessage(message: any) {
-    this.view?.webview.postMessage(message);
+    if (!this.view) return;
+    this.webviewMessageEmitter.fire({ direction: "toWebview", message });
+    this.view.webview.postMessage(message);
+  }
+
+  public dispose() {
+    this.messageEmitter.dispose();
+    this.webviewMessageEmitter.dispose();
   }
 
   /**