Update Canvas tests

src/Spectre.Console.Tests/Expectations/Widgets/Canvas/Render.Output.verified.txt

@@ -0,0 +1,5 @@
+          
+          
+          
+          
+          

src/Spectre.Console.Tests/Expectations/Widgets/Canvas/Render_MaxWidth.Output.verified.txt

@@ -0,0 +1,5 @@
+                    
+                    
+                    
+                    
+                    

src/Spectre.Console.Tests/Expectations/Widgets/Canvas/Render_NarrowTerminal.Output.verified.txt

@@ -0,0 +1,2 @@
+          
+          

src/Spectre.Console.Tests/Expectations/Widgets/Canvas/Render_Nested.Output.verified.txt

@@ -0,0 +1,4 @@
+┌──────┐
+│      │
+│      │
+└──────┘

src/Spectre.Console.Tests/Unit/CanvasTests.cs

@@ -1,57 +1,81 @@
 using System;
-using System.Linq;
+using System.Threading.Tasks;
-using System.Text;
 using Shouldly;
-using Spectre.Console.Rendering;
 using Spectre.Console.Testing;
+using Spectre.Verify.Extensions;
+using VerifyXunit;
 using Xunit;
 
 namespace Spectre.Console.Tests.Unit
 {
+    [UsesVerify]
+    [ExpectationPath("Widgets/Canvas")]
     public class CanvasTests
     {
-        [Fact]
+        public sealed class TheConstructor
-        public void Canvas_Must_Have_Proper_Size()
         {
-            Should.Throw<ArgumentException>(() => new Canvas(1, 0));
+            [Fact]
+            public void Should_Throw_If_Width_Is_Less_Than_Zero()
+            {
+                // Given, When
+                var result = Record.Exception(() => new Canvas(0, 1));
 
-            Should.Throw<ArgumentException>(() => new Canvas(0, 1));
+                // Then
+                result.ShouldBeOfType<ArgumentException>()
+                    .And(ex => ex.ParamName.ShouldBe("width"));
             }
 
             [Fact]
-        public void Simple_Render()
+            public void Should_Throw_If_Height_Is_Less_Than_Zero()
+            {
+                // Given, When
+                var result = Record.Exception(() => new Canvas(1, 0));
+
+                // Then
+                result.ShouldBeOfType<ArgumentException>()
+                    .And(ex => ex.ParamName.ShouldBe("height"));
+            }
+        }
+
+        [Fact]
+        [Expectation("Render")]
+        public async Task Should_Render_Canvas_Correctly()
         {
             // Given
             var console = new FakeAnsiConsole(ColorSystem.Standard);
-            var canvas = new Canvas(width: 2, height: 2);
+            var canvas = new Canvas(width: 5, height: 5);
-            canvas.SetPixel(0, 0, Color.Aqua);
+            canvas.SetPixel(0, 0, Color.Red);
-            canvas.SetPixel(1, 1, Color.Grey);
+            canvas.SetPixel(4, 0, Color.Green);
+            canvas.SetPixel(0, 4, Color.Blue);
+            canvas.SetPixel(4, 4, Color.Yellow);
 
             // When
             console.Render(canvas);
 
             // Then
-            console.Output.ShouldBe($"\u001b[106m  \u001b[0m  {Environment.NewLine}  \u001b[100m  \u001b[0m{Environment.NewLine}");
+            await Verifier.Verify(console.Output);
         }
 
         [Fact]
-        public void Render_Wider_Than_Terminal_Cannot_Be_Reduced_Further()
+        [Expectation("Render_Nested")]
+        public async Task Simple_Measure()
         {
             // Given
-            var console = new FakeAnsiConsole(ColorSystem.Standard, width: 10);
+            var console = new FakeAnsiConsole(ColorSystem.Standard);
-            var canvas = new Canvas(width: 20, height: 2);
+            var panel = new Panel(new Canvas(width: 2, height: 2)
-            canvas.SetPixel(0, 0, Color.Aqua);
+                .SetPixel(0, 0, Color.Aqua)
-            canvas.SetPixel(19, 1, Color.Grey);
+                .SetPixel(1, 1, Color.Grey));
 
             // When
-            console.Render(canvas);
+            console.Render(panel);
 
             // Then
-            console.Output.ShouldBe(string.Empty);
+            await Verifier.Verify(console.Output);
         }
 
         [Fact]
-        public void Render_Wider_Than_Terminal()
+        [Expectation("Render_NarrowTerminal")]
+        public async Task Should_Scale_Down_Canvas_Is_Bigger_Than_Terminal()
         {
             // Given
             var console = new FakeAnsiConsole(ColorSystem.Standard, width: 10);
@@ -63,46 +87,40 @@ namespace Spectre.Console.Tests.Unit
             console.Render(canvas);
 
             // Then
-            var numNewlines = console.Output.Count(x => x == '\n');
+            await Verifier.Verify(console.Output);
-
-            // Small terminal shrinks the canvas
-            numNewlines.ShouldBe(expected: 2);
         }
 
         [Fact]
-        public void Render_Wider_Configured_With_Max_Width()
+        [Expectation("Render_MaxWidth")]
+        public async Task Should_Scale_Down_Canvas_If_MaxWidth_Is_Set()
         {
             // Given
             var console = new FakeAnsiConsole(ColorSystem.Standard, width: 80);
             var canvas = new Canvas(width: 20, height: 10) { MaxWidth = 10 };
             canvas.SetPixel(0, 0, Color.Aqua);
-            canvas.SetPixel(19, 9, Color.Grey);
+            canvas.SetPixel(19, 9, Color.Aqua);
 
             // When
             console.Render(canvas);
 
             // Then
-            var numNewlines = console.Output.Count(x => x == '\n');
+            await Verifier.Verify(console.Output);
-
-            // MaxWidth truncates the canvas
-            numNewlines.ShouldBe(expected: 5);
         }
 
         [Fact]
-        public void Simple_Measure()
+        public void Should_Not_Render_Canvas_If_Canvas_Cannot_Be_Scaled_Down()
         {
             // Given
-            var console = new FakeAnsiConsole(ColorSystem.Standard);
+            var console = new FakeAnsiConsole(ColorSystem.Standard, width: 10);
-            var canvas = new Canvas(width: 2, height: 2);
+            var canvas = new Canvas(width: 20, height: 2);
             canvas.SetPixel(0, 0, Color.Aqua);
-            canvas.SetPixel(1, 1, Color.Grey);
+            canvas.SetPixel(19, 1, Color.Grey);
 
             // When
-            var measurement = ((IRenderable)canvas).Measure(new RenderContext(Encoding.Unicode, false), 80);
+            console.Render(canvas);
 
             // Then
-            measurement.Max.ShouldBe(expected: 4);
+            console.Output.ShouldBeEmpty();
-            measurement.Min.ShouldBe(expected: 4);
         }
     }
 }

src/Spectre.Console/Widgets/Canvas.cs

@@ -66,9 +66,11 @@ namespace Spectre.Console
         /// <param name="x">The X coordinate for the pixel.</param>
         /// <param name="y">The Y coordinate for the pixel.</param>
         /// <param name="color">The pixel color.</param>
-        public void SetPixel(int x, int y, Color color)
+        /// <returns>The same <see cref="Canvas"/> instance so that multiple calls can be chained.</returns>
+        public Canvas SetPixel(int x, int y, Color color)
         {
             _pixels[x, y] = color;
+            return this;
         }
 
         /// <inheritdoc/>