Add GetValueOrDefault extension methods for Guid

Co-authored-by: marcominerva <3522534+marcominerva@users.noreply.github.com>

Author: Copilot

src/TinyHelpers/Extensions/GuidExtensions.cs

@@ -70,6 +70,15 @@ public static bool HasValue([NotNullWhen(true)] this Guid? input)
     public static Guid GetValueOrCreateNew(this Guid input)
         => input.IsEmpty() ? Guid.NewGuid() : input;
 
+    /// <summary>
+    /// Gets the actual value of this <see cref="Guid"/> instance, if it is different from <c>Guid.Empty</c>; otherwise, returns the specified default value.
+    /// </summary>
+    /// <param name="input">The <see cref="Guid"/> to test.</param>
+    /// <param name="defaultValue">The default <see cref="Guid"/> to return if the input is <c>Guid.Empty</c>.</param>
+    /// <returns>The actual value of this <see cref="Guid"/> instance, if it is different from <c>Guid.Empty</c>; otherwise, the specified default value.</returns>
+    public static Guid GetValueOrDefault(this Guid input, Guid defaultValue)
+        => input.IsEmpty() ? defaultValue : input;
+
     /// <summary>
     /// Gets the actual value of this <see cref="Guid"/> instance, if it is different from <see langword="null"/> and <c>Guid.Empty</c>; otherwise, creates a new <see cref="Guid"/> using <see cref="Guid.NewGuid()"/>.
     /// </summary>
@@ -78,6 +87,15 @@ public static Guid GetValueOrCreateNew(this Guid input)
     public static Guid GetValueOrCreateNew(this Guid? input)
         => input.IsEmpty() ? Guid.NewGuid() : input!.Value;
 
+    /// <summary>
+    /// Gets the actual value of this <see cref="Guid"/> instance, if it is different from <see langword="null"/> and <c>Guid.Empty</c>; otherwise, returns the specified default value.
+    /// </summary>
+    /// <param name="input">The <see cref="Guid"/> to test.</param>
+    /// <param name="defaultValue">The default <see cref="Guid"/> to return if the input is <see langword="null"/> or <c>Guid.Empty</c>.</param>
+    /// <returns>The actual value of this <see cref="Guid"/> instance, if it is different from <see langword="null"/> and <c>Guid.Empty</c>; otherwise, the specified default value.</returns>
+    public static Guid GetValueOrDefault(this Guid? input, Guid defaultValue)
+        => input.IsEmpty() ? defaultValue : input!.Value;
+
 #if NET9_0_OR_GREATER
     /// <summary>
     /// Gets the actual value of this <see cref="Guid"/> instance, if it is different from <c>Guid.Empty</c>; otherwise, creates a new <see cref="Guid"/> using <see cref="Guid.NewGuid()"/>.

tests/TinyHelpers.Tests/Extensions/GuidExtensionsTests.cs

@@ -212,4 +212,74 @@ public void NullableGuidIsNotEmpty_GetValueOrCreateNew_Should_Return_TheSameGuid
         // Assert
         Assert.Equal(input, value);
     }
+
+    [Fact]
+    public void GuidIsEmpty_GetValueOrDefault_Should_Return_DefaultValue()
+    {
+        // Arrange
+        var input = Guid.Empty;
+        var defaultValue = Guid.NewGuid();
+
+        // Act
+        var value = input.GetValueOrDefault(defaultValue);
+
+        // Assert
+        Assert.Equal(defaultValue, value);
+    }
+
+    [Fact]
+    public void GuidIsNotEmpty_GetValueOrDefault_Should_Return_TheSameGuid()
+    {
+        // Arrange
+        var input = Guid.NewGuid();
+        var defaultValue = Guid.NewGuid();
+
+        // Act
+        var value = input.GetValueOrDefault(defaultValue);
+
+        // Assert
+        Assert.Equal(input, value);
+    }
+
+    [Fact]
+    public void NullableGuidIsEmpty_GetValueOrDefault_Should_Return_DefaultValue()
+    {
+        // Arrange
+        Guid? input = Guid.Empty;
+        var defaultValue = Guid.NewGuid();
+
+        // Act
+        var value = input.GetValueOrDefault(defaultValue);
+
+        // Assert
+        Assert.Equal(defaultValue, value);
+    }
+
+    [Fact]
+    public void NullableGuidIsNull_GetValueOrDefault_Should_Return_DefaultValue()
+    {
+        // Arrange
+        Guid? input = null;
+        var defaultValue = Guid.NewGuid();
+
+        // Act
+        var value = input.GetValueOrDefault(defaultValue);
+
+        // Assert
+        Assert.Equal(defaultValue, value);
+    }
+
+    [Fact]
+    public void NullableGuidIsNotEmpty_GetValueOrDefault_Should_Return_TheSameGuid()
+    {
+        // Arrange
+        Guid? input = Guid.NewGuid();
+        var defaultValue = Guid.NewGuid();
+
+        // Act
+        var value = input.GetValueOrDefault(defaultValue);
+
+        // Assert
+        Assert.Equal(input, value);
+    }
 }