test: add unit tests for ReadonlyContext

core/test/agents/readonly_context_test.ts

@@ -0,0 +1,117 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  InvocationContext,
+  LlmAgent,
+  PluginManager,
+  ReadonlyContext,
+  Session,
+} from '@google/adk';
+import {Content} from '@google/genai';
+import {describe, expect, it} from 'vitest';
+
+function makeSession(overrides: Partial<Session> = {}): Session {
+  return {
+    id: 'session-1',
+    appName: 'test-app',
+    userId: 'user-1',
+    state: {},
+    events: [],
+    lastUpdateTime: Date.now(),
+    ...overrides,
+  } as Session;
+}
+
+function makeInvocationContext(
+  overrides: Partial<{
+    invocationId: string;
+    userContent: Content;
+    session: Session;
+    agentName: string;
+  }> = {},
+): InvocationContext {
+  const agent = new LlmAgent({name: overrides.agentName ?? 'test-agent'});
+  const session = overrides.session ?? makeSession();
+
+  return new InvocationContext({
+    invocationId: overrides.invocationId ?? 'inv-123',
+    agent,
+    session,
+    userContent: overrides.userContent,
+    pluginManager: new PluginManager(),
+  });
+}
+
+describe('ReadonlyContext', () => {
+  it('should construct without errors given a minimal InvocationContext', () => {
+    const ic = makeInvocationContext();
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx).toBeInstanceOf(ReadonlyContext);
+  });
+
+  it('invocationId delegates to the underlying InvocationContext', () => {
+    const ic = makeInvocationContext({invocationId: 'my-inv-id'});
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.invocationId).toBe('my-inv-id');
+  });
+
+  it('userId delegates to the underlying session userId', () => {
+    const session = makeSession({userId: 'alice'});
+    const ic = makeInvocationContext({session});
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.userId).toBe('alice');
+  });
+
+  it('sessionId delegates to the underlying session id', () => {
+    const session = makeSession({id: 'sess-42'});
+    const ic = makeInvocationContext({session});
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.sessionId).toBe('sess-42');
+  });
+
+  it('agentName delegates to the underlying agent name', () => {
+    const ic = makeInvocationContext({agentName: 'my-agent'});
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.agentName).toBe('my-agent');
+  });
+
+  it('userContent delegates to the underlying InvocationContext userContent', () => {
+    const content: Content = {
+      role: 'user',
+      parts: [{text: 'hello'}],
+    };
+    const ic = makeInvocationContext({userContent: content});
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.userContent).toEqual(content);
+  });
+
+  it('userContent is undefined when not set on InvocationContext', () => {
+    const ic = makeInvocationContext();
+    const ctx = new ReadonlyContext(ic);
+    expect(ctx.userContent).toBeUndefined();
+  });
+
+  it('state returns a State wrapping the session state values', () => {
+    const session = makeSession({state: {foo: 'bar', count: 42}});
+    const ic = makeInvocationContext({session});
+    const ctx = new ReadonlyContext(ic);
+    const state = ctx.state;
+    expect(state.get('foo')).toBe('bar');
+    expect(state.get('count')).toBe(42);
+  });
+
+  it('state returns a new State instance on each access', () => {
+    const session = makeSession({state: {x: 1}});
+    const ic = makeInvocationContext({session});
+    const ctx = new ReadonlyContext(ic);
+    const state1 = ctx.state;
+    const state2 = ctx.state;
+    // Each call returns a new wrapper around the same underlying data
+    expect(state1).not.toBe(state2);
+    expect(state1.get('x')).toBe(state2.get('x'));
+  });
+});