diff --git a/.github/workflows/mention-to-chatwork.yml b/.github/workflows/mention-to-chatwork.yml
index 1512fb7..67264a2 100644
--- a/.github/workflows/mention-to-chatwork.yml
+++ b/.github/workflows/mention-to-chatwork.yml
@@ -32,9 +32,12 @@ jobs:
         run: |
           npm install
           npm run build
+          mkdir act
+          cp -r dist act
+          cp action.yml act
 
       - name: test run
-        uses: ./
+        uses: ./act
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           api-token: ${{ secrets.CHATWORK_API_TOKEN }}
diff --git a/src/domain/github.ts b/src/domain/github.ts
index 21cb325..1d028b6 100644
--- a/src/domain/github.ts
+++ b/src/domain/github.ts
@@ -1,5 +1,4 @@
 import { context } from "@actions/github";
-import { stringify } from "ts-jest";
 import { WebhookPayload } from "@actions/github/lib/interfaces";
 import { convertToChatworkUsername, MappingFile } from "../model";
 import * as core from "@actions/core";
@@ -31,7 +30,7 @@ const acceptActionTypes = {
 };
 
 const buildError = (payload: unknown): Error => {
-  return new Error(`unknown event hook: ${stringify(payload)}`);
+  return new Error(`unknown event hook: ${JSON.stringify(payload)}`);
 };
 
 export const needToSendApproveMention = (payload: WebhookPayload): boolean => {
diff --git a/src/main.ts b/src/main.ts
index ea8a6ee..6798c3d 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,5 +1,3 @@
-import { stringify } from "ts-jest";
-
 import * as core from "@actions/core";
 import { context } from "@actions/github";
 
@@ -18,16 +16,16 @@ export const main = async (): Promise<void> => {
   core.info("start main");
 
   const { payload } = context;
-  core.info(stringify(payload));
+  core.info(JSON.stringify(payload));
 
   const allInputs = getAllInputs();
-  core.info(stringify(allInputs));
+  core.info(JSON.stringify(allInputs));
 
   const { repoToken, configurationPath, reviewRequest } = allInputs;
 
   try {
     const mapping = await execLoadMapping(configurationPath, repoToken);
-    core.info(stringify(mapping));
+    core.info(JSON.stringify(mapping));
 
     if (reviewRequest) {
       await execPrReviewRequestedMention(payload, allInputs, mapping);
diff --git a/src/model.ts b/src/model.ts
index 5a20ce5..ba745c6 100644
--- a/src/model.ts
+++ b/src/model.ts
@@ -1,5 +1,4 @@
 import * as core from "@actions/core";
-import { stringify } from "ts-jest";
 
 export type AllInputs = {
   repoToken: string;
@@ -45,12 +44,12 @@ export const convertToChatworkUsername = (
   githubUsernames: string[],
   mapping: MappingFile,
 ): Account[] => {
-  core.info(stringify(githubUsernames));
+  core.info(JSON.stringify(githubUsernames));
 
   const slackIds = githubUsernames.map(
     (githubUsername) => mapping[githubUsername],
   );
-  core.info(stringify(slackIds));
+  core.info(JSON.stringify(slackIds));
 
   return slackIds;
 };