Fix Align measure to respect explicitly set width

.gitignore

@@ -54,6 +54,7 @@ src/.idea/**/uiDesigner.xml
 [Dd]ebug/
 [Rr]elease/
 x64/
+*.lscache
 *_i.c
 *_p.c
 *.ilk

src/Spectre.Console.Tests/Expectations/Public_API.Output.verified.txt

@@ -7,6 +7,7 @@
         public Spectre.Console.HorizontalAlignment Horizontal { get; set; }
         public Spectre.Console.VerticalAlignment? Vertical { get; set; }
         public int? Width { get; set; }
+        protected override Spectre.Console.Rendering.Measurement Measure(Spectre.Console.Rendering.RenderOptions options, int maxWidth) { }
         protected override System.Collections.Generic.IEnumerable<Spectre.Console.Rendering.Segment> Render(Spectre.Console.Rendering.RenderOptions options, int maxWidth) { }
         public static Spectre.Console.Align Center(Spectre.Console.Rendering.IRenderable renderable, Spectre.Console.VerticalAlignment? vertical = default) { }
         public static Spectre.Console.Align Left(Spectre.Console.Rendering.IRenderable renderable, Spectre.Console.VerticalAlignment? vertical = default) { }

src/Spectre.Console.Tests/Unit/Widgets/AlignTests.cs

@@ -146,4 +146,21 @@ public Task Should_Render_Panel_Right_Aligned_At_Bottom()
             return Verifier.Verify(console.Output);
         }
     }
+    public sealed class Measure
+    {
+        [Fact]
+        public void Should_Return_Explicit_Width_When_Set()
+        {
+            // Given
+            var console = new TestConsole().Size(new Size(40, 15));
+            var align = Align.Left(new Panel("Hello World!")).Width(20);
+
+            // When
+            var measurement = ((IRenderable)align)
+                .Measure(RenderOptions.Create(console), 40);
+
+            // Then
+            Assert.Equal(20, measurement.Max);
+        }
+    }
 }

src/Spectre.Console/Widgets/Align.cs

@@ -74,6 +74,14 @@ public static Align Right(IRenderable renderable, VerticalAlignment? vertical =
         return new Align(renderable, HorizontalAlignment.Right, vertical);
     }
 
+    /// <inheritdoc/>
+    protected override Measurement Measure(RenderOptions options, int maxWidth)
+    {
+        var width = Math.Min(Width ?? maxWidth, maxWidth);
+        var measurement = _renderable.Measure(options with { Height = null }, width);
+        return new Measurement(Math.Min(measurement.Min, width), width);
+    }
+
     /// <inheritdoc/>
     protected override IEnumerable<Segment> Render(RenderOptions options, int maxWidth)
     {