Add Test

Author: thecoolwinter

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager.swift

@@ -55,7 +55,14 @@ public class TextLayoutManager: NSObject {
         }
     }
 
-    public weak var renderDelegate: TextLayoutManagerRenderDelegate?
+    public weak var renderDelegate: TextLayoutManagerRenderDelegate? {
+        didSet {
+            // Rebuild using potentially overridden behavior.
+            _estimateLineHeight = nil
+            lineStorage.removeAll()
+            prepareTextLines()
+        }
+    }
 
     // MARK: - Internal
 

Tests/CodeEditTextViewTests/OverridingLayoutManagerRenderingTests.swift

@@ -12,6 +12,8 @@ class MockRenderDelegate: TextLayoutManagerRenderDelegate {
         _ breakStrategy: LineBreakStrategy
     ) -> Void)?
 
+    var estimatedLineHeightOverride: (() -> CGFloat)?
+
     func prepareForDisplay( // swiftlint:disable:this function_parameter_count
         textLine: TextLine,
         displayData: TextLine.DisplayData,
@@ -35,6 +37,10 @@ class MockRenderDelegate: TextLayoutManagerRenderDelegate {
             breakStrategy: breakStrategy
         )
     }
+
+    func estimatedLineHeight() -> CGFloat? {
+        estimatedLineHeightOverride?()
+    }
 }
 
 @Suite
@@ -92,4 +98,17 @@ struct OverridingLayoutManagerRenderingTests {
         #expect(layoutManager.lineStorage.height == 14.0)
         layoutManager.lineStorage.validateInternalState()
     }
+
+    @Test
+    func overriddenEstimatedLineHeight() {
+        // The layout manager should use the estimation from the render delegate, not the font size.
+        mockDelegate.estimatedLineHeightOverride = {
+            1.0
+        }
+
+        layoutManager.renderDelegate = mockDelegate
+
+        #expect(layoutManager.estimateLineHeight() == 1.0)
+        #expect(layoutManager.estimatedHeight() == 4.0) // 4 lines, each 1 high
+    }
 }