diff --git a/spec/index.spec.ts b/spec/index.spec.ts
index 2904409..2fefa1d 100644
--- a/spec/index.spec.ts
+++ b/spec/index.spec.ts
@@ -67,6 +67,7 @@ describe('index', () => {
 
 import './lifecycle.spec';
 import './main.spec';
+import './secretmanager.spec';
 import './v2.spec';
 import './cloudevent/generate';
 import './app.spec';
diff --git a/spec/secretmanager.spec.ts b/spec/secretmanager.spec.ts
new file mode 100644
index 0000000..6df0cbe
--- /dev/null
+++ b/spec/secretmanager.spec.ts
@@ -0,0 +1,46 @@
+import { expect } from 'chai';
+import { mockSecretManager } from '../src/secretManager';
+
+describe('mockSecretManager', () => {
+  let originalEnv;
+
+  before(() => {
+    // Capture the original environment variables
+    originalEnv = { ...process.env };
+  });
+
+  afterEach(() => {
+    // Reset any mutations made by the test run
+    process.env = { ...originalEnv };
+  });
+
+  it('applies each key/value pair to process.env', () => {
+    const conf = { FOO: 'bar', BAZ: 'qux' };
+
+    mockSecretManager(conf);
+
+    expect(process.env.FOO).to.equal('bar');
+    expect(process.env.BAZ).to.equal('qux');
+  });
+
+  it('overwrites an existing variable with the new value', () => {
+    process.env.EXISTING = 'old';
+    const conf = { EXISTING: 'new' };
+
+    mockSecretManager(conf);
+
+    expect(process.env.EXISTING).to.equal('new');
+  });
+
+  it('supports non-string values (coerced to string)', () => {
+    const conf: Record<string, string> = {
+      NUM_VALUE: '123',
+      BOOL_VALUE: 'true',
+    };
+
+    mockSecretManager(conf);
+
+    expect(process.env.NUM_VALUE).to.equal('123');
+    expect(process.env.BOOL_VALUE).to.equal('true');
+  });
+});
diff --git a/src/main.ts b/src/main.ts
index a2e621d..13a23bb 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -45,6 +45,8 @@ type HttpsFunctionOrCloudFunctionV1<T, U> = U extends HttpsFunction &
   ? HttpsFunction & Runnable<T>
   : CloudFunctionV1<T>;
 
+export { mockSecretManager } from './secretManager';
+
 // Re-exporting V1 (to reduce breakage)
 export {
   ContextOptions,
diff --git a/src/secretManager.ts b/src/secretManager.ts
new file mode 100644
index 0000000..3156845
--- /dev/null
+++ b/src/secretManager.ts
@@ -0,0 +1,6 @@
+/** Mock values returned by `functions.config()`. */
+export function mockSecretManager(conf: Record<string, string>) {
+  for (const [key, value] of Object.entries(conf)) {
+    process.env[key] = value;
+  }
+}