diff --git a/test/GitHubExtension/DeveloperId/CredentialVaultTests.cs b/test/GitHubExtension/DeveloperId/CredentialVaultTests.cs
new file mode 100644
index 0000000..4dc7871
--- /dev/null
+++ b/test/GitHubExtension/DeveloperId/CredentialVaultTests.cs
@@ -0,0 +1,106 @@
+// Copyright (c) Microsoft Corporation and Contributors
+// Licensed under the MIT license.
+
+using System.Net;
+using GitHubExtension.DeveloperId;
+
+namespace GitHubExtension.Test;
+
+// Unit Tests for CredentialVault
+public partial class DeveloperIdTests
+{
+    [TestMethod]
+    [TestCategory("Unit")]
+    public void CredentialVault_CreateSingleton()
+    {
+        var credentialVault1 = new CredentialVault("DevHomeGitHubExtensionTest");
+        Assert.IsNotNull(credentialVault1);
+
+        var credentialVault2 = new CredentialVault("DevHomeGitHubExtensionTest");
+        Assert.IsNotNull(credentialVault2);
+
+        Assert.AreNotEqual(credentialVault1, credentialVault2);
+
+        credentialVault1.RemoveAllCredentials();
+        Assert.AreEqual(0, credentialVault1.GetAllCredentials().Count());
+    }
+
+    [TestMethod]
+    [TestCategory("LiveData")]
+    [DataRow("testuser1")]
+    [DataRow("https://github.com/testuser2")]
+    [DataRow("https://RandomWebServer.example/testuser3")]
+    public void CredentialVault_SaveAndRetrieveCredential(string loginId)
+    {
+        var credentialVault = new CredentialVault("DevHomeGitHubExtensionTest");
+        Assert.IsNotNull(credentialVault);
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+
+        var nullCredential = credentialVault.GetCredentials(loginId);
+        Assert.IsNull(nullCredential);
+
+        var testCredential = "testcredential";
+
+        var credential = new NetworkCredential(null, testCredential).SecurePassword;
+        credentialVault.SaveCredentials(loginId, credential);
+
+        var retrievedCredential = credentialVault.GetCredentials(loginId);
+        Assert.IsNotNull(retrievedCredential);
+        Assert.AreEqual(testCredential, retrievedCredential.Password);
+
+        credentialVault.RemoveAllCredentials();
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+    }
+
+    [TestMethod]
+    [TestCategory("LiveData")]
+    [DataRow("testuser1")]
+    [DataRow("https://github.com/testuser2")]
+    [DataRow("https://RandomWebServer.example/testuser3")]
+    public void CredentialVault_RemoveAndRetrieveCredential(string loginId)
+    {
+        var credentialVault = new CredentialVault("DevHomeGitHubExtensionTest");
+        Assert.IsNotNull(credentialVault);
+
+        var testCredential = "testCredential";
+
+        var credential = new NetworkCredential(null, testCredential).SecurePassword;
+        credentialVault.SaveCredentials(loginId, credential);
+
+        var retrievedCredential = credentialVault.GetCredentials(loginId);
+        Assert.IsNotNull(retrievedCredential);
+        Assert.AreEqual(testCredential, retrievedCredential.Password);
+
+        credentialVault.RemoveCredentials(loginId);
+
+        var nullCredential = credentialVault.GetCredentials(loginId);
+        Assert.IsNull(nullCredential);
+
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+    }
+
+    [TestMethod]
+    [TestCategory("LiveData")]
+    public void CredentialVault_GetAllCredentials()
+    {
+        var credentialVault = new CredentialVault("DevHomeGitHubExtensionTest");
+        Assert.IsNotNull(credentialVault);
+
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+
+        var testLoginId = "testuser1";
+        var testCredential = "testCredential";
+
+        var credential = new NetworkCredential(null, testCredential).SecurePassword;
+        credentialVault.SaveCredentials(testLoginId, credential);
+
+        Assert.AreEqual(1, credentialVault.GetAllCredentials().Count());
+
+        credentialVault.RemoveCredentials(testLoginId);
+
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+
+        var nullCredential = credentialVault.GetCredentials(testLoginId);
+        Assert.IsNull(nullCredential);
+    }
+}
diff --git a/test/GitHubExtension/DeveloperId/DeveloperIdProviderTests.cs b/test/GitHubExtension/DeveloperId/DeveloperIdProviderTests.cs
index b419d8d..838fb0a 100644
--- a/test/GitHubExtension/DeveloperId/DeveloperIdProviderTests.cs
+++ b/test/GitHubExtension/DeveloperId/DeveloperIdProviderTests.cs
@@ -56,6 +56,32 @@ private CredentialVault SetupCredentialVaultWithGHESTestUser()
         return credentialVault;
     }
 
+    /* Tests depend on the following environment variables:
+     * DEV_HOME_TEST_GITHUB_COM_USER : Url for a test user on github.com
+     * DEV_HOME_TEST_GITHUB_COM_PAT : Personal Access Token for the test user on github.com
+     * DEV_HOME_TEST_GITHUB_ENTERPRISE_SERVER_USER : Url for a test user on GHES
+     * DEV_HOME_TEST_GITHUB_ENTERPRISE_SERVER_PAT : Personal Access Token for the test user on the GHES
+     */
+    private CredentialVault SetupCredentialVaultWithMultipleTestUsers()
+    {
+        var credentialVault = SetupCleanCredentialVaultClean();
+
+        var testLoginId = Environment.GetEnvironmentVariable("DEV_HOME_TEST_GITHUB_COM_USER") ?? string.Empty;
+        var testPassword = Environment.GetEnvironmentVariable("DEV_HOME_TEST_GITHUB_COM_PAT");
+
+        var testGHESLoginId = Environment.GetEnvironmentVariable("DEV_HOME_TEST_GITHUB_ENTERPRISE_SERVER_USER") ?? string.Empty;
+        var testGHESPassword = Environment.GetEnvironmentVariable("DEV_HOME_TEST_GITHUB_ENTERPRISE_SERVER_PAT");
+
+        var password = new NetworkCredential(null, testPassword).SecurePassword;
+        credentialVault.SaveCredentials(testLoginId, password);
+
+        var ghesPassword = new NetworkCredential(null, testGHESPassword).SecurePassword;
+        credentialVault.SaveCredentials(testGHESLoginId, ghesPassword);
+
+        Assert.AreEqual(2, credentialVault.GetAllCredentials().Count());
+        return credentialVault;
+    }
+
     private CredentialVault SetupCredentialVaultWithInvalidTestUser()
     {
         var credentialVault = SetupCleanCredentialVaultClean();
@@ -129,6 +155,31 @@ public void DeveloperIdProvider_RestoreAndGetDeveloperIds()
         Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
     }
 
+    [TestMethod]
+    [TestCategory("LiveData")]
+    public void DeveloperIdProvider_RestoreAndGetMultipleDeveloperIds()
+    {
+        // Setup CredentialVault with a dummy testuser and valid PAT for Github.com
+        var credentialVault = SetupCredentialVaultWithMultipleTestUsers();
+
+        // Test whether the DeveloperIdProvider can restore the saved credentials
+        var devIdProvider = DeveloperIdProvider.GetInstance();
+        Assert.IsNotNull(devIdProvider);
+        var result = devIdProvider.GetLoggedInDeveloperIds();
+
+        Assert.IsNotNull(result);
+        Assert.AreEqual(ProviderOperationStatus.Success, result.Result.Status);
+        Assert.AreEqual(2, result.DeveloperIds.Count());
+        Assert.AreNotEqual("dummytestuser1", result.DeveloperIds.First().LoginId);
+        Assert.AreNotEqual("dummytestuser1", result.DeveloperIds.Last().LoginId);
+        Assert.IsNotNull(new Uri(result.DeveloperIds.First().Url));
+        Assert.IsNotNull(new Uri(result.DeveloperIds.Last().Url));
+
+        // Cleanup
+        credentialVault.RemoveAllCredentials();
+        Assert.AreEqual(0, credentialVault.GetAllCredentials().Count());
+    }
+
     [TestMethod]
     [TestCategory("LiveData")]
     public void DeveloperIdProvider_GetDeveloperIds_InvalidPAT()