PM-3925 - Tech Debt - Add missed tests for SSO Email 2FA Tokenable (#3270)

* PM-3925 - (1) Slightly refactor SsoEmail2faSessionTokenable to provide public static GetTokenLifeTime() method for testing  (2) Add missed tests to SsoEmail2faSessionTokenable

* PM-3925 - Take into account PR feedback

src/Core/Auth/Models/Business/Tokenables/SsoEmail2faSessionTokenable.cs

@@ -6,11 +6,12 @@ namespace Bit.Core.Auth.Models.Business.Tokenables;
 
 // This token just provides a verifiable authN mechanism for the API service
 // TwoFactorController.cs SendEmailLogin anonymous endpoint so it cannot be
-// used maliciously. 
+// used maliciously.
 public class SsoEmail2faSessionTokenable : ExpiringTokenable
 {
     // Just over 2 min expiration (client expires session after 2 min)
-    private static readonly TimeSpan _tokenLifetime = TimeSpan.FromMinutes(2.05);
+    public static TimeSpan GetTokenLifetime() => TimeSpan.FromMinutes(2.05);
+
     public const string ClearTextPrefix = "BwSsoEmail2FaSessionToken_";
     public const string DataProtectorPurpose = "SsoEmail2faSessionTokenDataProtector";
 
@@ -24,7 +25,7 @@ public class SsoEmail2faSessionTokenable : ExpiringTokenable
     [JsonConstructor]
     public SsoEmail2faSessionTokenable()
     {
-        ExpirationDate = DateTime.UtcNow.Add(_tokenLifetime);
+        ExpirationDate = DateTime.UtcNow.Add(GetTokenLifetime());
     }
 
     public SsoEmail2faSessionTokenable(User user) : this()
@@ -44,7 +45,7 @@ public class SsoEmail2faSessionTokenable : ExpiringTokenable
                Email.Equals(user.Email, StringComparison.InvariantCultureIgnoreCase);
     }
 
-    // Validates deserialized 
+    // Validates deserialized
     protected override bool TokenIsValid() =>
         Identifier == TokenIdentifier && Id != default && !string.IsNullOrWhiteSpace(Email);
 }

test/Core.Test/Auth/Models/Business/Tokenables/SsoEmail2faSessionTokenableTests.cs

@@ -0,0 +1,173 @@
+using AutoFixture.Xunit2;
+using Bit.Core.Auth.Models.Business.Tokenables;
+using Bit.Core.Entities;
+using Bit.Core.Tokens;
+using Xunit;
+namespace Bit.Core.Test.Auth.Models.Business.Tokenables;
+
+// Note: these test names follow MethodName_StateUnderTest_ExpectedBehavior pattern.
+public class SsoEmail2faSessionTokenableTests
+{
+    // Allow a small tolerance for possible execution delays or clock precision to avoid flaky tests.
+    private static readonly TimeSpan _timeTolerance = TimeSpan.FromMilliseconds(10);
+
+    /// <summary>
+    /// Tests the default constructor behavior when passed a null user.
+    /// </summary>
+    [Fact]
+    public void Constructor_NullUser_PropertiesSetToDefault()
+    {
+        var token = new SsoEmail2faSessionTokenable(null);
+
+        Assert.Equal(default, token.Id);
+        Assert.Equal(default, token.Email);
+    }
+
+    /// <summary>
+    /// Tests that when a valid user is provided to the constructor, the resulting token properties match the user.
+    /// </summary>
+    [Theory, AutoData]
+    public void Constructor_ValidUser_PropertiesSetFromUser(User user)
+    {
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        Assert.Equal(user.Id, token.Id);
+        Assert.Equal(user.Email, token.Email);
+    }
+
+    /// <summary>
+    /// Tests the default expiration behavior immediately after initialization.
+    /// </summary>
+    [Fact]
+    public void Constructor_AfterInitialization_ExpirationSetToExpectedDuration()
+    {
+        var token = new SsoEmail2faSessionTokenable();
+        var expectedExpiration = DateTime.UtcNow + SsoEmail2faSessionTokenable.GetTokenLifetime();
+
+        Assert.True(expectedExpiration - token.ExpirationDate < _timeTolerance);
+    }
+
+    /// <summary>
+    /// Tests that a custom expiration date is preserved after token initialization.
+    /// </summary>
+    [Fact]
+    public void Constructor_CustomExpirationDate_ExpirationMatchesProvidedValue()
+    {
+        var customExpiration = DateTime.UtcNow.AddHours(3);
+        var token = new SsoEmail2faSessionTokenable
+        {
+            ExpirationDate = customExpiration
+        };
+
+        Assert.True((customExpiration - token.ExpirationDate).Duration() < _timeTolerance);
+    }
+
+    /// <summary>
+    /// Tests the validity of a token initialized with a null user.
+    /// </summary>
+    [Fact]
+    public void Valid_NullUser_ReturnsFalse()
+    {
+        var token = new SsoEmail2faSessionTokenable(null);
+
+        Assert.False(token.Valid);
+    }
+
+    /// <summary>
+    /// Tests the validity of a token with a non-matching identifier.
+    /// </summary>
+    [Theory, AutoData]
+    public void Valid_WrongIdentifier_ReturnsFalse(User user)
+    {
+        var token = new SsoEmail2faSessionTokenable(user)
+        {
+            Identifier = "not correct"
+        };
+
+        Assert.False(token.Valid);
+    }
+
+    /// <summary>
+    /// Tests the token validity when user ID is null.
+    /// </summary>
+    [Theory, AutoData]
+    public void TokenIsValid_NullUserId_ReturnsFalse(User user)
+    {
+        user.Id = default; // Guid.Empty
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        Assert.False(token.TokenIsValid(user));
+    }
+
+    /// <summary>
+    /// Tests the token validity when user's email is null.
+    /// </summary>
+    [Theory, AutoData]
+    public void TokenIsValid_NullEmail_ReturnsFalse(User user)
+    {
+        user.Email = null;
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        Assert.False(token.TokenIsValid(user));
+    }
+
+    /// <summary>
+    /// Tests the token validity when user ID and email match the token properties.
+    /// </summary>
+    [Theory, AutoData]
+    public void TokenIsValid_MatchingUserIdAndEmail_ReturnsTrue(User user)
+    {
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        Assert.True(token.TokenIsValid(user));
+    }
+
+    /// <summary>
+    /// Ensures that the token is invalid when the provided user's ID doesn't match the token's ID.
+    /// </summary>
+    [Theory, AutoData]
+    public void TokenIsValid_WrongUserId_ReturnsFalse(User user)
+    {
+        // Given a token initialized with a user's details
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        // modify the user's ID
+        user.Id = Guid.NewGuid();
+
+        // Then the token should be considered invalid
+        Assert.False(token.TokenIsValid(user));
+    }
+
+    /// <summary>
+    /// Ensures that the token is invalid when the provided user's email doesn't match the token's email.
+    /// </summary>
+    [Theory, AutoData]
+    public void TokenIsValid_WrongEmail_ReturnsFalse(User user)
+    {
+        // Given a token initialized with a user's details
+        var token = new SsoEmail2faSessionTokenable(user);
+
+        // modify the user's email
+        user.Email = "nonMatchingEmail@example.com";
+
+        // Then the token should be considered invalid
+        Assert.False(token.TokenIsValid(user));
+    }
+
+    /// <summary>
+    /// Tests the deserialization of a token to ensure that the expiration date is preserved.
+    /// </summary>
+    [Theory, AutoData]
+    public void FromToken_SerializedToken_PreservesExpirationDate(User user)
+    {
+        var expectedDateTime = DateTime.UtcNow.AddHours(-5);
+        var token = new SsoEmail2faSessionTokenable(user)
+        {
+            ExpirationDate = expectedDateTime
+        };
+
+        var result = Tokenable.FromToken<SsoEmail2faSessionTokenable>(token.ToToken());
+
+        Assert.Equal(expectedDateTime, result.ExpirationDate, precision: _timeTolerance);
+    }
+}