diff --git a/cdk/cloudformation.ts b/cdk/cloudformation.ts
index 4c3d04f..5a0c214 100644
--- a/cdk/cloudformation.ts
+++ b/cdk/cloudformation.ts
@@ -1,58 +1,13 @@
 import { TestApp } from './TestApp'
-import * as path from 'path'
-import { promises as fs } from 'fs'
-import { getLambdaSourceCodeBucketName } from './getLambdaSourceCodeBucketName'
-import { TestStackLambdas } from './TestStack'
-import { packBaseLayer, packLayeredLambdas, WebpackMode } from '../src'
+import { prepareResources } from './prepareResources'
 
 const stackName = process.env.STACK_NAME
 
-if (!stackName) {
+if (stackName === undefined) {
 	console.error(`STACK_NAME not set!`)
 	process.exit(1)
 }
 
-const prepareResources = async ({
-	stackName,
-	rootDir,
-}: {
-	stackName: string
-	rootDir: string
-}) => {
-	// Pack the lambdas
-	const outDir = path.resolve(rootDir, 'dist', 'lambdas')
-	try {
-		await fs.stat(outDir)
-	} catch (_) {
-		await fs.mkdir(outDir)
-	}
-	const sourceCodeBucketName = await getLambdaSourceCodeBucketName({
-		stackName,
-	})
-	const baseLayerZipFileName = await packBaseLayer({
-		srcDir: rootDir,
-		outDir,
-		Bucket: sourceCodeBucketName,
-	})
-	const lambdas = await packLayeredLambdas<TestStackLambdas>({
-		id: 'test-lambdas',
-		mode: WebpackMode.production,
-		srcDir: rootDir,
-		outDir,
-		Bucket: sourceCodeBucketName,
-		lambdas: {
-			uuid: path.resolve(rootDir, 'test', 'uuidLambda.ts'),
-		},
-		tsConfig: path.resolve(rootDir, 'tsconfig.json'),
-	})
-
-	return {
-		sourceCodeBucketName,
-		baseLayerZipFileName,
-		lambdas,
-	}
-}
-
 prepareResources({
 	stackName,
 	rootDir: process.cwd(),
diff --git a/cdk/prepareResources.ts b/cdk/prepareResources.ts
new file mode 100644
index 0000000..12aea08
--- /dev/null
+++ b/cdk/prepareResources.ts
@@ -0,0 +1,55 @@
+import * as path from 'path'
+import { promises as fs } from 'fs'
+import { getLambdaSourceCodeBucketName } from './getLambdaSourceCodeBucketName'
+import { TestStackLambdas } from './TestStack'
+import {
+	packBaseLayer,
+	packLayeredLambdas,
+	WebpackMode,
+	LayeredLambdas,
+} from '../src'
+
+export const prepareResources = async ({
+	stackName,
+	rootDir,
+}: {
+	stackName: string
+	rootDir: string
+}): Promise<{
+	sourceCodeBucketName: string
+	baseLayerZipFileName: string
+	lambdas: LayeredLambdas<TestStackLambdas>
+}> => {
+	// Pack the lambdas
+	const outDir = path.resolve(rootDir, 'dist', 'lambdas')
+	try {
+		await fs.stat(outDir)
+	} catch (_) {
+		await fs.mkdir(outDir)
+	}
+	const sourceCodeBucketName = await getLambdaSourceCodeBucketName({
+		stackName,
+	})
+	const baseLayerZipFileName = await packBaseLayer({
+		srcDir: rootDir,
+		outDir,
+		Bucket: sourceCodeBucketName,
+	})
+	const lambdas = await packLayeredLambdas<TestStackLambdas>({
+		id: 'test-lambdas',
+		mode: WebpackMode.production,
+		srcDir: rootDir,
+		outDir,
+		Bucket: sourceCodeBucketName,
+		lambdas: {
+			uuid: path.resolve(rootDir, 'test', 'uuidLambda.ts'),
+		},
+		tsConfig: path.resolve(rootDir, 'tsconfig.json'),
+	})
+
+	return {
+		sourceCodeBucketName,
+		baseLayerZipFileName,
+		lambdas,
+	}
+}