Add unit tests for token refresh handling in OAuth2TokenManager

- Introduced new test cases in `OAuth2TokenManager` to verify the handling of token refresh when the token is within the buffer time, ensuring that valid tokens are correctly returned.
- Added tests for concurrent token refresh requests to ensure that multiple simultaneous requests are handled properly, returning the expected new access token.
- Included tests for handling null and undefined token data in `setTokenDataForTesting`, ensuring that the token manager correctly identifies invalid token states.

These updates enhance the reliability and robustness of the OAuth2 token management implementation by validating critical scenarios related to token refresh behavior and data integrity.

Author: anatolyshipitz

workers/main/src/services/OAuth2/OAuth2TokenManager.basic.test.ts

@@ -159,4 +159,18 @@ describe('OAuth2TokenManager - Basic', () => {
     tokenManager.setTokenDataForTesting(tokenData);
     expect(tokenManager.isTokenValid()).toBe(false);
   });
+
+  it('should handle token refresh when token is within buffer time', async () => {
+    const tokenData: TokenData = {
+      access_token: 'valid-token',
+      refresh_token: 'refresh-token',
+      expires_at: Date.now() + 600000,
+      token_type: 'Bearer',
+    };
+
+    tokenManager.setTokenDataForTesting(tokenData);
+    const accessToken = await tokenManager.getAccessToken();
+
+    expect(accessToken).toBe('valid-token');
+  });
 });

workers/main/src/services/OAuth2/OAuth2TokenManager.storage.test.ts

@@ -36,7 +36,6 @@ describe('OAuth2TokenManager - Storage & Edge Cases', () => {
 
   beforeEach(async () => {
     tokenManager = new OAuth2TokenManager('qbo', 'test-refresh-token');
-    // Wait for async initialization to complete
     await new Promise((resolve) => setTimeout(resolve, 0));
   });
 
@@ -112,4 +111,51 @@ describe('OAuth2TokenManager - Storage & Edge Cases', () => {
   it('should return default refresh token when no cached token', () => {
     expect(tokenManager.getCurrentRefreshToken()).toBe('test-refresh-token');
   });
+
+  it('should handle token refresh when token is within buffer time', async () => {
+    const tokenData: TokenData = {
+      access_token: 'valid-token',
+      refresh_token: 'refresh-token',
+      expires_at: Date.now() + 600000,
+      token_type: 'Bearer',
+    };
+
+    tokenManager.setTokenDataForTesting(tokenData);
+    const accessToken = await tokenManager.getAccessToken();
+
+    expect(accessToken).toBe('valid-token');
+  });
+
+  it('should handle concurrent token refresh requests', async () => {
+    const expiredTokenData: TokenData = {
+      access_token: 'expired-token',
+      refresh_token: 'refresh-token',
+      expires_at: Date.now() - 3600000,
+      token_type: 'Bearer',
+    };
+
+    tokenManager.setTokenDataForTesting(expiredTokenData);
+
+    const promises = [
+      tokenManager.getAccessToken(),
+      tokenManager.getAccessToken(),
+      tokenManager.getAccessToken(),
+    ];
+
+    const results = await Promise.all(promises);
+
+    results.forEach((result) => {
+      expect(result).toBe('new-access-token');
+    });
+  });
+
+  it('should handle setTokenDataForTesting with null data', () => {
+    tokenManager.setTokenDataForTesting(null as unknown as TokenData);
+    expect(tokenManager.isTokenValid()).toBe(false);
+  });
+
+  it('should handle setTokenDataForTesting with undefined data', () => {
+    tokenManager.setTokenDataForTesting(undefined as unknown as TokenData);
+    expect(tokenManager.isTokenValid()).toBe(false);
+  });
 });