Fix Tests

Author: swhitty

SwiftDrawTests/MockRenderer.swift

@@ -130,7 +130,7 @@ final class MockRenderer: Renderer {
     operations.append("drawLinearGradient")
   }
 
-  func draw(radial gradient: LayerTree.Gradient, at center: LayerTree.Point, radius: LayerTree.Float) {
+  func draw(radial gradient: LayerTree.Gradient, startCenter: LayerTree.Point, startRadius: LayerTree.Float, endCenter: LayerTree.Point, endRadius: LayerTree.Float) {
     operations.append("drawRadialGradient")
   }
 }

SwiftDrawTests/RendererTests.swift

@@ -60,7 +60,7 @@ final class RendererTests: XCTestCase {
       .setBlend(mode: .sourceIn),
       .draw(image: .mock),
       .drawLinearGradient(.mock, from: .zero, to: .zero),
-      .drawRadialGradient(.mock, center: .zero, radius: 100)
+      .drawRadialGradient(.mock, startCenter: .zero, startRadius: 0, endCenter: .zero, endRadius: 0)
     ])
 
     XCTAssertEqual(renderer.operations, [