ScrollView infinity safety

BlueprintUICommonControls/Sources/ScrollView.swift

@@ -198,8 +198,12 @@ extension ScrollView {
             result.width += contentInset.left + contentInset.right
             result.height += contentInset.top + contentInset.bottom
 
-            result.width = min(result.width, proposal.width.maximum)
-            result.height = min(result.height, proposal.height.maximum)
+            if let maxWidth = proposal.width.constrainedValue {
+                result.width = min(result.width, maxWidth)
+            }
+            if let maxHeight = proposal.height.constrainedValue {
+                result.height = min(result.height, maxHeight)
+            }
 
             return result
         }
@@ -210,6 +214,8 @@ extension ScrollView {
             insetSize.height -= contentInset.top + contentInset.bottom
 
             var itemSize = fittedSize(in: .init(insetSize), subelement: subelement)
+                .replacingInfinity(with: insetSize)
+
             if contentSize == .fittingHeight {
                 itemSize.width = insetSize.width
             } else if contentSize == .fittingWidth {

BlueprintUICommonControls/Tests/Sources/ScrollViewTests.swift

@@ -15,6 +15,50 @@ import BlueprintUI
 
 class ScrollViewTests: XCTestCase {
 
+    // When a scrollview places a subelement that has an infinite size, it defaults to replacing
+    // those dimensions with the size of the scrollview itself.
+    func test_infiniteContent() throws {
+
+        struct InfiniteBox: Element {
+            var content: ElementContent {
+                ElementContent(intrinsicSize: .infinity)
+            }
+
+            func backingViewDescription(with context: ViewDescriptionContext) -> ViewDescription? {
+                UIView.describe { view in
+                    view[\.backgroundColor] = .red
+                }
+            }
+        }
+
+        compareSnapshot(
+            of: InfiniteBox()
+                .scrollable(.fittingContent)
+                .inset(uniform: 10),
+            size: CGSize(width: 100, height: 100),
+            identifier: "fittingContent",
+            layoutModes: [.caffeinated]
+        )
+
+        compareSnapshot(
+            of: InfiniteBox()
+                .scrollable(.fittingWidth)
+                .inset(uniform: 10),
+            size: CGSize(width: 100, height: 100),
+            identifier: "fittingWidth",
+            layoutModes: [.caffeinated]
+        )
+
+        compareSnapshot(
+            of: InfiniteBox()
+                .scrollable(.fittingHeight)
+                .inset(uniform: 10),
+            size: CGSize(width: 100, height: 100),
+            identifier: "fittingHeight",
+            layoutModes: [.caffeinated]
+        )
+    }
+
     func test_calculateContentInset() {
         // No inset
 

BlueprintUICommonControls/Tests/Sources/XCTestCaseExtensions.swift

@@ -101,22 +101,33 @@ extension XCTestCase {
         size: CGSize? = nil,
         identifier: String? = nil,
         scale: CGFloat = 1,
+        layoutModes: [LayoutMode] = LayoutMode.testModes,
         file: StaticString = #file,
         testName: String = #function,
         line: UInt = #line
     ) {
-        let view = BlueprintView(element: element)
-        view.name = "Snapshot Host"
+        for layoutMode in layoutModes {
+            let view = BlueprintView(element: element)
+            view.name = "Snapshot Host"
+            view.layoutMode = layoutMode
 
-        if let size = size {
-            view.frame = CGRect(origin: .zero, size: size)
-        } else {
-            view.sizeToFit()
-            view.frame.size.width.round(.up, by: scale)
-            view.frame.size.height.round(.up, by: scale)
-        }
+            if let size = size {
+                view.frame = CGRect(origin: .zero, size: size)
+            } else {
+                view.sizeToFit()
+                view.frame.size.width.round(.up, by: scale)
+                view.frame.size.height.round(.up, by: scale)
+            }
 
-        compareSnapshot(of: view, identifier: identifier, scale: scale, file: file, testName: testName, line: line)
+            compareSnapshot(
+                of: view,
+                identifier: identifier,
+                scale: scale,
+                file: file,
+                testName: testName,
+                line: line
+            )
+        }
     }
 
 }