ILSpy/ILSpy.Tests/Resources/IconCompositionTests.cs

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using Avalonia.Headless.NUnit;

using AwesomeAssertions;

using ILSpy.Images;

using NUnit.Framework;

namespace ICSharpCode.ILSpy.Tests;

[TestFixture]
public class IconCompositionTests
{
	[AvaloniaTest]
	public void Public_Method_Has_No_Overlays_And_Full_Sized_Base()
	{
		// Public members are the unmarked default — no accessibility overlay glyph and no
		// shrinkdown; the base image renders 1:1.

		// Arrange + Act — request a Public Method icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Method, AccessOverlayIcon.Public);

		// Assert — base is the Method bitmap, no overlays, full scale.
		icon.BaseImage.Should().BeSameAs(Images.Method);
		icon.Overlays.Should().BeEmpty();
		icon.BaseScale.Should().Be(1.0);
	}

	[AvaloniaTest]
	public void Private_Method_Composes_Method_Plus_OverlayPrivate_At_80_Percent()
	{
		// Adding an accessibility overlay (Private here) shrinks the base to 80% so the overlay
		// glyph has visual room to sit in the bottom-right corner.

		// Arrange + Act — request a Private Method icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Method, AccessOverlayIcon.Private);

		// Assert — base shrinks to 0.8, exactly one overlay (the Private padlock).
		icon.BaseImage.Should().BeSameAs(Images.Method);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayPrivate);
	}

	[AvaloniaTest]
	public void Static_Public_Field_Composes_Field_Plus_OverlayStatic_At_80_Percent()
	{
		// `static` adds a Static overlay glyph even when the member is Public — any non-default
		// modifier triggers the 0.8 base shrink.

		// Arrange + Act — request a static Public Field icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Field, AccessOverlayIcon.Public, isStatic: true);

		// Assert — base shrinks to 0.8 with just the Static glyph layered on top.
		icon.BaseImage.Should().BeSameAs(Images.Field);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayStatic);
	}

	[AvaloniaTest]
	public void Extension_Method_Composes_Method_Plus_OverlayExtension_At_80_Percent()
	{
		// Extension methods get the dedicated Extension overlay even when the member is Public.

		// Arrange + Act — request a Public extension Method icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Method, AccessOverlayIcon.Public, isExtension: true);

		// Assert — base shrinks to 0.8 with the Extension glyph as the lone overlay.
		icon.BaseImage.Should().BeSameAs(Images.Method);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayExtension);
	}

	[AvaloniaTest]
	public void Static_Private_Method_Layers_Static_Then_Private_Over_Method_At_80_Percent()
	{
		// Order matters: the layering sequence (extension → static → accessibility) determines
		// which glyphs end up on top when corners overlap. A static private method must layer
		// Static under Private so the accessibility glyph remains visible.

		// Arrange + Act — request a static Private Method icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Method, AccessOverlayIcon.Private, isStatic: true);

		// Assert — overlays are Static followed by Private (back-to-front draw order).
		icon.BaseImage.Should().BeSameAs(Images.Method);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayStatic, Images.OverlayPrivate);
	}

	[AvaloniaTest]
	public void Static_Extension_Method_Layers_Extension_Then_Static_Then_Internal()
	{
		// All three modifiers at once exercises the full layering rule: extension → static →
		// accessibility, in that draw order.

		// Arrange + Act — request an internal static extension Method icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Method, AccessOverlayIcon.Internal,
			isStatic: true, isExtension: true);

		// Assert — three overlays in the documented order.
		icon.BaseImage.Should().BeSameAs(Images.Method);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayExtension, Images.OverlayStatic, Images.OverlayInternal);
	}

	[AvaloniaTest]
	public void Protected_Event_Composes_Event_Plus_OverlayProtected()
	{
		// Sanity-check that the same composition rules apply across base bitmaps (Event here,
		// not just Method/Field).

		// Arrange + Act — request a Protected Event icon.
		var icon = (LayeredImage)Images.GetIcon(Images.Event, AccessOverlayIcon.Protected);

		// Assert — base shrinks to 0.8 with the Protected glyph as the lone overlay.
		icon.BaseImage.Should().BeSameAs(Images.Event);
		icon.BaseScale.Should().Be(0.8);
		icon.Overlays.Should().Equal(Images.OverlayProtected);
	}

	[AvaloniaTest]
	public void GetIcon_Caches_Same_Composition()
	{
		// Decompiling a large assembly produces hundreds of identically-decorated members;
		// GetIcon must memoise on (base, overlay, isStatic, isExtension) so we don't recreate
		// the same LayeredImage repeatedly.

		// Arrange + Act — request the same composition twice.
		var first = Images.GetIcon(Images.Property, AccessOverlayIcon.Internal);
		var second = Images.GetIcon(Images.Property, AccessOverlayIcon.Internal);

		// Assert — reference equality proves caching.
		first.Should().BeSameAs(second, "GetIcon must memoise by (base, overlay, isStatic, isExtension)");
	}
}