diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..9aac95c
--- /dev/null
+++ b/.env.example
@@ -0,0 +1 @@
+GITHUB_TOKEN_TEST=
\ No newline at end of file
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 2bd36fa..825497c 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -30,6 +30,4 @@ jobs:
         with:
           commit: "chore: update versions"
           title: "chore: update versions"
-          publish: bunx changeset publish
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
\ No newline at end of file
+          publish: bunx changeset publish
\ No newline at end of file
diff --git a/.github/workflows/testing.yml b/.github/workflows/testing.yml
new file mode 100644
index 0000000..455edb4
--- /dev/null
+++ b/.github/workflows/testing.yml
@@ -0,0 +1,20 @@
+name: "Testing"
+on:
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    name: test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repo
+        uses: actions/checkout@v4
+      - name: Install bun
+        uses: oven-sh/setup-bun@v1
+      - name: Install dependencies
+        run: bun install
+      - name: Run tests
+        run: bun test
+        env:
+          GITHUB_TOKEN_TEST: ${{ secrets.GITHUB_TOKEN }}
\ No newline at end of file
diff --git a/README.md b/README.md
index 8f58cbe..eda1ca2 100644
--- a/README.md
+++ b/README.md
@@ -83,3 +83,15 @@ bun run pkg <pkg-name> <script-name>
 # all packages
 bun run pkg-all <script-name>
 ```
+
+## Environement Variables
+
+Depending on your development activity, you may need to set some environment variables for the packages to work properly or to run tests.
+
+```bash
+cp env.example .env
+```
+
+Fill in the values in the .env file.
+
+Ideally, `GITHUB_TOKEN_TEST` should have same permissions as testing CI:
diff --git a/packages/collaborators/index.test.ts b/packages/collaborators/index.test.ts
new file mode 100644
index 0000000..b3cbf04
--- /dev/null
+++ b/packages/collaborators/index.test.ts
@@ -0,0 +1,73 @@
+import { describe, test, expect } from 'bun:test';
+import {
+  getCollaborators,
+  getCollaboratorsResponseSchema,
+  getCollaboratorsResponseInvalidSchema,
+  type GetCollaboratorsResponse,
+  type GetCollaboratorsProps,
+} from './index';
+
+describe('collaborators', () => {
+  test('valid', async () => {
+    try {
+      const collaborator = (await getCollaborators({
+        owner: 'privanote',
+        repo: 'privanote',
+        token: process.env.GITHUB_TOKEN_TEST as string,
+      })) as GetCollaboratorsResponse[];
+
+      if (Array.isArray(collaborator)) {
+        const result = collaborator
+          .map((c) => getCollaboratorsResponseSchema.safeParse(c).success)
+          .includes(false);
+        expect(result).toBe(false);
+      } else {
+        expect().fail(
+          'This should not be reached: ' + JSON.stringify(collaborator),
+        );
+      }
+    } catch (error) {
+      const tokenIssue =
+        error instanceof Error ? error.message.includes('token') : false;
+
+      if (tokenIssue) {
+        expect().fail('Invalid token provided');
+      } else {
+        expect().fail('This should not be reached: ' + error);
+      }
+    }
+  });
+
+  test('invalid repo or token', async () => {
+    try {
+      const collaborator = (await getCollaborators({
+        owner: 'privanote',
+        repo: 'asdfasfdasdfsadfsasdfasdf',
+        token: process.env.GITHUB_TOKEN_TEST as string,
+      })) as GetCollaboratorsResponse[];
+
+      const result =
+        getCollaboratorsResponseInvalidSchema.safeParse(collaborator).success;
+
+      expect(result).toBe(true);
+    } catch (error) {
+      const tokenIssue =
+        error instanceof Error ? error.message.includes('token') : false;
+
+      if (tokenIssue) {
+        expect().fail('Invalid token provided');
+      } else {
+        expect().fail('This should not be reached: ' + error);
+      }
+    }
+  });
+
+  test('error', async () => {
+    try {
+      await getCollaborators({} as GetCollaboratorsProps);
+    } catch (error) {
+      const result = error instanceof Error;
+      expect(result).toBe(true);
+    }
+  });
+});
diff --git a/packages/collaborators/index.ts b/packages/collaborators/index.ts
index 70e5c53..c4f6f71 100644
--- a/packages/collaborators/index.ts
+++ b/packages/collaborators/index.ts
@@ -6,7 +6,7 @@ const getCollaboratorsPropsSchema = z.object({
   token: z.string(),
 });
 
-const getCollaboratorsResponseSchema = z.object({
+export const getCollaboratorsResponseSchema = z.object({
   login: z.string(),
   id: z.number(),
   node_id: z.string(),
@@ -35,8 +35,18 @@ const getCollaboratorsResponseSchema = z.object({
   role_name: z.string(),
 });
 
-type GetCollaboratorsResponse = z.infer<typeof getCollaboratorsResponseSchema>;
-type GetCollaboratorsProps = z.infer<typeof getCollaboratorsPropsSchema>;
+export const getCollaboratorsResponseInvalidSchema = z.object({
+  message: z.string(),
+  documentation_url: z.string(),
+});
+
+export type GetCollaboratorsResponse = z.infer<
+  typeof getCollaboratorsResponseSchema
+>;
+export type GetCollaboratorsResponseInvalid = z.infer<
+  typeof getCollaboratorsResponseInvalidSchema
+>;
+export type GetCollaboratorsProps = z.infer<typeof getCollaboratorsPropsSchema>;
 
 /**
  * Get the list of collaborators for a repository
@@ -63,13 +73,15 @@ export const getCollaborators = async ({
     );
     const data = await response.json();
     if (!response.ok) {
-      return data as { message: string; documentation_url: string };
+      return data as GetCollaboratorsResponseInvalid;
     } else {
       return data as GetCollaboratorsResponse[];
     }
   } catch (error: unknown) {
     if (error instanceof Error) {
       throw new Error(`Error: ${error.message}`);
+    } else {
+      throw new Error('An unknown error occurred');
     }
   }
 };