diff --git a/docs/pages/guides/pages/signin.mdx b/docs/pages/guides/pages/signin.mdx
index 96e6113f1a..644ec9feb9 100644
--- a/docs/pages/guides/pages/signin.mdx
+++ b/docs/pages/guides/pages/signin.mdx
@@ -99,6 +99,7 @@ We can now build our own custom sign in page.
 
 ```tsx filename="app/signin/page.tsx" /providerMap/
 import { signIn, auth, providerMap } from "@/auth.ts"
+import { AuthError } from 'next-auth'
 
 export default async function SignInPage() {
   return (
@@ -107,7 +108,20 @@ export default async function SignInPage() {
         <form
           action={async () => {
             "use server"
-            await signIn(provider.id)
+            try {
+              await signIn(provider.id)
+            } catch (error) {
+              // Signin can fail for a number of reasons, such as the user
+              // not existing, or the user not having the correct role.
+              // In some cases, you may want to redirect to a custom error
+              if (error instanceof AuthError) {
+                return redirect(`${SIGNIN_ERROR_URL}?error=${error.type}`)
+              }
+
+              // Otherwise if a redirects happens NextJS can handle it
+              // so you can just re-thrown the error and let NextJS handle it.
+              throw error
+            }
           }}
         >
           <button type="submit">
diff --git a/docs/pages/reference/_meta.js b/docs/pages/reference/_meta.js
index 94ae23065a..388200c2c6 100644
--- a/docs/pages/reference/_meta.js
+++ b/docs/pages/reference/_meta.js
@@ -41,4 +41,5 @@ export default {
   "unstorage-adapter": "@auth/unstorage-adapter",
   "upstash-redis-adapter": "@auth/upstash-redis-adapter",
   "xata-adapter": "@auth/xata-adapter",
+  "test-adapter": "@auth/test-adapter",
 }
diff --git a/packages/adapter-test/README.md b/packages/adapter-test/README.md
new file mode 100644
index 0000000000..ef771112f2
--- /dev/null
+++ b/packages/adapter-test/README.md
@@ -0,0 +1,25 @@
+<p align="center">
+  <br/>
+  <a href="https://authjs.dev" target="_blank">
+    <img height="64px" src="https://authjs.dev/img/logo-sm.png" />
+  </a>
+  <h3 align="center"><b>Test Adapter</b> - NextAuth.js / Auth.js</a></h3>
+  <p align="center" style="align: center;">
+    <a href="https://npm.im/@auth/pg-adapter">
+      <img src="https://img.shields.io/badge/TypeScript-blue?style=flat-square" alt="TypeScript" />
+    </a>
+    <a href="https://npm.im/@auth/test-adapter">
+      <img alt="npm" src="https://img.shields.io/npm/v/@auth/pg-adapter?color=green&label=@auth/test-adapter&style=flat-square">
+    </a>
+    <a href="https://www.npmtrends.com/@auth/pg-adapter">
+      <img src="https://img.shields.io/npm/dm/@auth/test-adapter?label=%20downloads&style=flat-square" alt="Downloads" />
+    </a>
+    <a href="https://github.com/nextauthjs/next-auth/stargazers">
+      <img src="https://img.shields.io/github/stars/nextauthjs/next-auth?style=flat-square" alt="GitHub Stars" />
+    </a>
+  </p>
+</p>
+
+---
+
+Check out the documentation at [authjs.dev](https://authjs.dev/reference/adapter/test).
diff --git a/packages/adapter-test/package.json b/packages/adapter-test/package.json
new file mode 100644
index 0000000000..4446b01883
--- /dev/null
+++ b/packages/adapter-test/package.json
@@ -0,0 +1,44 @@
+{
+  "name": "@auth/test-adapter",
+  "version": "0.1.0",
+  "description": "Testing adapter for next-auth.",
+  "homepage": "https://authjs.dev",
+  "repository": "https://github.com/nextauthjs/next-auth",
+  "bugs": {
+    "url": "https://github.com/nextauthjs/next-auth/issues"
+  },
+  "author": "Jake Coppinger",
+  "contributors": [
+    "Thang Huu Vu <hi@thvu.dev>"
+  ],
+  "license": "ISC",
+  "keywords": [
+    "next-auth",
+    "@auth",
+    "Auth.js",
+    "next.js",
+    "oauth"
+  ],
+  "type": "module",
+  "exports": {
+    ".": {
+      "types": "./index.d.ts",
+      "import": "./index.js"
+    }
+  },
+  "files": [
+    "*.d.ts*",
+    "*.js",
+    "src"
+  ],
+  "private": false,
+  "publishConfig": {
+    "access": "public"
+  },
+  "scripts": {
+    "build": "tsc"
+  },
+  "dependencies": {
+    "@auth/core": "workspace:*"
+  }
+}
diff --git a/packages/adapter-test/src/index.ts b/packages/adapter-test/src/index.ts
new file mode 100644
index 0000000000..4f5ea4d72c
--- /dev/null
+++ b/packages/adapter-test/src/index.ts
@@ -0,0 +1,110 @@
+import {
+  Adapter,
+  AdapterSession,
+  AdapterUser,
+  VerificationToken,
+  AdapterAccount,
+} from "@auth/core/adapters"
+
+export function TestAdapter(): Adapter {
+  let user: AdapterUser | null = null
+  let session: AdapterSession | null = null
+  let account: AdapterAccount | null = null
+  let verificationToken: VerificationToken | null = null
+  return {
+    async createUser(data: AdapterUser) {
+      user = data
+      return user
+    },
+    async getUser(userId: string) {
+      return user && user.id === userId ? user : null
+    },
+    async getUserByEmail(email: string) {
+      return user && user.email === email ? user : null
+    },
+    async createSession(data: {
+      sessionToken: string
+      userId: string
+      expires: Date
+    }) {
+      session = {
+        sessionToken: data.sessionToken,
+        userId: data.userId,
+        expires: data.expires,
+      }
+      return Promise.resolve(session)
+    },
+    async getSessionAndUser(sessionToken: string) {
+      const result =
+        session && session.sessionToken === sessionToken
+          ? { session: session!, user: user! }
+          : null
+      return Promise.resolve(result)
+    },
+    async updateUser(data: Partial<AdapterUser> & Pick<AdapterUser, "id">) {
+      if (user?.id !== data.id) {
+        throw new Error("No user id.")
+      }
+
+      user = { ...user, ...data }
+      return user
+    },
+    async updateSession(
+      data: Partial<AdapterSession> & Pick<AdapterSession, "sessionToken">
+    ) {
+      if (!session || session.sessionToken !== data.sessionToken) return null
+
+      session = { ...session, ...data }
+      return session
+    },
+    async linkAccount(data: AdapterAccount) {
+      account = data
+      return Promise.resolve(account)
+    },
+    async getUserByAccount(
+      input: Pick<AdapterAccount, "provider" | "providerAccountId">
+    ) {
+      return account &&
+        account.provider === input.provider &&
+        account.providerAccountId === input.providerAccountId
+        ? user
+        : null
+    },
+    async deleteSession(sessionToken: string) {
+      if (!session || session.sessionToken !== sessionToken) return null
+      session = null
+    },
+    async createVerificationToken(data: VerificationToken) {
+      verificationToken = data
+      return verificationToken
+    },
+    async useVerificationToken(params: { identifier: string; token: string }) {
+      if (!verificationToken) return null
+      if (
+        verificationToken.identifier === params.identifier &&
+        verificationToken.token === params.token
+      ) {
+        verificationToken = null
+        return verificationToken
+      }
+
+      return null
+    },
+    async deleteUser(id: string) {
+      if (user?.id !== id) return undefined
+      user = null
+    },
+    async unlinkAccount(
+      params: Pick<AdapterAccount, "provider" | "providerAccountId">
+    ) {
+      if (
+        !account ||
+        account.provider !== params.provider ||
+        account.providerAccountId !== params.providerAccountId
+      ) {
+        return undefined
+      }
+      account = null
+    },
+  }
+}
diff --git a/packages/adapter-test/tsconfig.json b/packages/adapter-test/tsconfig.json
new file mode 100644
index 0000000000..df8621c516
--- /dev/null
+++ b/packages/adapter-test/tsconfig.json
@@ -0,0 +1,9 @@
+{
+  "extends": "utils/tsconfig.json",
+  "compilerOptions": {
+    "outDir": ".",
+    "rootDir": "src"
+  },
+  "exclude": ["*.js", "*.d.ts"],
+  "include": ["src/**/*"]
+}
diff --git a/packages/adapter-test/typedoc.config.cjs b/packages/adapter-test/typedoc.config.cjs
new file mode 100644
index 0000000000..b5103c3a1b
--- /dev/null
+++ b/packages/adapter-test/typedoc.config.cjs
@@ -0,0 +1,14 @@
+// @ts-check
+
+/**
+ * @type {import('typedoc').TypeDocOptions & import('typedoc-plugin-markdown').MarkdownTheme}
+ */
+module.exports = {
+  entryPoints: ["src/index.ts"],
+  entryPointStrategy: "expand",
+  tsconfig: "./tsconfig.json",
+  entryModule: "@auth/test-adapter",
+  entryFileName: "../test-adapter.mdx",
+  includeVersion: true,
+  readme: 'none',
+}
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index f88617a9d3..a7ce393ab6 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -170,7 +170,9 @@ export async function Auth(
     return Response.json({ url }, { headers: response.headers })
   } catch (e) {
     const error = e as Error
-    logger.error(error)
+    if (process.env.NODE_ENV !== "test") {
+      logger.error(error)
+    }
 
     const isAuthError = error instanceof AuthError
     if (isAuthError && isRaw && !isRedirect) throw error
diff --git a/packages/next-auth/package.json b/packages/next-auth/package.json
index eeb2b65098..72dde01969 100644
--- a/packages/next-auth/package.json
+++ b/packages/next-auth/package.json
@@ -66,6 +66,7 @@
     "clean": "rm -rf *.js *.d.ts* lib providers",
     "dev": "pnpm providers && tsc -w",
     "test": "vitest run -c ../utils/vitest.config.ts",
+    "test:watch": "vitest -c ../utils/vitest.config.ts",
     "providers": "node ../utils/scripts/providers"
   },
   "files": [
@@ -99,6 +100,7 @@
   },
   "devDependencies": {
     "@types/react": "18.0.37",
+    "@auth/test-adapter": "workspace:*",
     "next": "14.0.3-canary.1",
     "nodemailer": "^6.9.3",
     "react": "^18.2.0"
diff --git a/packages/next-auth/src/lib/actions.test.ts b/packages/next-auth/src/lib/actions.test.ts
new file mode 100644
index 0000000000..b98ef0fadb
--- /dev/null
+++ b/packages/next-auth/src/lib/actions.test.ts
@@ -0,0 +1,109 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest"
+import { signIn } from "./actions"
+import { EmailProviderType } from "../providers"
+import { TestAdapter } from "@auth/test-adapter"
+import { NextAuthConfig } from "."
+
+let mockedHeaders = vi.hoisted(() => {
+  return new globalThis.Headers()
+})
+
+const mockRedirect = vi.hoisted(() => vi.fn())
+vi.mock("next/navigation", async (importOriginal) => {
+  const originalModule = await importOriginal()
+  return {
+    // @ts-expect-error - not typed
+    ...originalModule,
+    redirect: mockRedirect,
+  }
+})
+
+vi.mock("next/headers", async (importOriginal) => {
+  const originalModule = await importOriginal()
+  return {
+    // @ts-expect-error - not typed
+    ...originalModule,
+    headers: () => mockedHeaders,
+    cookies: () => {
+      const cookies: { [key: string]: unknown } = {}
+      return {
+        get: (name: string) => {
+          return cookies[name]
+        },
+        set: (name: string, value: string) => {
+          cookies[name] = value
+        },
+      }
+    },
+  }
+})
+
+let options = {
+  redirectTo: "http://localhost/dashboard",
+  email: "jane@example.com",
+}
+let authorizationParams = {}
+let config: NextAuthConfig = {
+  secret: ["supersecret"],
+  trustHost: true,
+  basePath: "/api/auth",
+  adapter: TestAdapter(),
+  providers: [
+    {
+      id: "nodemailer",
+      type: "email" as EmailProviderType,
+      name: "Email",
+      from: "no-reply@authjs.dev",
+      maxAge: 86400,
+      sendVerificationRequest: async () => { },
+      options: {},
+    },
+  ],
+}
+
+describe("signIn", () => {
+  beforeEach(() => {
+    process.env.NEXTAUTH_URL = "http://localhost"
+  })
+
+  afterEach(() => {
+    process.env.NEXTAUTH_URL = undefined
+  })
+
+  it("redirects to verify URL", async () => {
+    await signIn("nodemailer", options, authorizationParams, config)
+
+    expect(mockRedirect).toHaveBeenCalledWith(
+      "http://localhost/api/auth/verify-request?provider=nodemailer&type=email"
+    )
+  })
+
+  it("redirects to error URL", async () => {
+    config = {
+      ...config,
+      providers: [
+        {
+          id: "nodemailer",
+          type: "email" as EmailProviderType,
+          name: "Email",
+          from: "no-reply@authjs.dev",
+          maxAge: 86400,
+          sendVerificationRequest: async () => {
+            throw new Error("IGNORE_ERROR_IN_TEST_STACK")
+          },
+          options: {},
+        },
+      ],
+    }
+    let redirectTo: string | undefined | null
+    redirectTo = await signIn(
+      "nodemailer",
+      { ...options, redirect: false },
+      authorizationParams,
+      config
+    )
+    expect(redirectTo).toEqual(
+      "http://localhost/api/auth/error?error=Configuration"
+    )
+  })
+})
diff --git a/packages/next-auth/src/lib/actions.ts b/packages/next-auth/src/lib/actions.ts
index 77b56667a8..e197bf29f2 100644
--- a/packages/next-auth/src/lib/actions.ts
+++ b/packages/next-auth/src/lib/actions.ts
@@ -2,11 +2,9 @@ import { Auth, raw, skipCSRFCheck, createActionURL } from "@auth/core"
 import { headers as nextHeaders, cookies } from "next/headers"
 import { redirect } from "next/navigation"
 
-import type { AuthAction } from "@auth/core/types"
 import type { NextAuthConfig } from "./index.js"
 import type { NextAuthResult, Session } from "../index.js"
 import type { ProviderType } from "@auth/core/providers"
-import type { headers } from "next/headers"
 
 type SignInParams = Parameters<NextAuthResult["signIn"]>
 export async function signIn(
@@ -73,8 +71,12 @@ export async function signIn(
 
   for (const c of res?.cookies ?? []) cookies().set(c.name, c.value, c.options)
 
-  if (shouldRedirect) return redirect(res.redirect!)
-  return res.redirect as any
+  const responseUrl =
+    res instanceof Response ? res.headers.get("Location") : res.redirect
+
+  if (shouldRedirect) return redirect(responseUrl!)
+
+  return responseUrl as any
 }
 
 type SignOutParams = Parameters<NextAuthResult["signOut"]>
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 101347e8d0..575ee44bea 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -555,6 +555,12 @@ importers:
         specifier: ^0.11.0
         version: 0.11.0
 
+  packages/adapter-test:
+    dependencies:
+      '@auth/core':
+        specifier: workspace:*
+        version: link:../core
+
   packages/adapter-typeorm:
     dependencies:
       '@auth/core':
@@ -782,6 +788,9 @@ importers:
         specifier: ^9.0.2
         version: 9.0.2(encoding@0.1.13)
     devDependencies:
+      '@auth/test-adapter':
+        specifier: workspace:*
+        version: link:../adapter-test
       '@types/react':
         specifier: 18.0.37
         version: 18.0.37