Add TextLayoutManager Tests

Author: thecoolwinter

Sources/CodeEditTextView/TextLayoutManager/TextLayoutManager+Edits.swift

@@ -72,7 +72,7 @@ extension TextLayoutManager: NSTextStorageDelegate {
             }
         }
     }
-    
+
     /// Inserts any newly inserted lines into the line layout storage. Exits early if the range is empty.
     /// - Parameter range: The range of the string that was inserted into the text storage.
     private func insertNewLines(for range: NSRange) {
@@ -97,7 +97,7 @@ extension TextLayoutManager: NSTextStorageDelegate {
     ///   - location: The location the string is being inserted into.
     private func applyLineInsert(_ insertedString: NSString, at location: Int) {
         if LineEnding(line: insertedString as String) != nil {
-            if location == textStorage?.length ?? 0 {
+            if location == lineStorage.length {
                 // Insert a new line at the end of the document, need to insert a new line 'cause there's nothing to
                 // split. Also, append the new text to the last line.
                 lineStorage.update(atIndex: location, delta: insertedString.length, deltaHeight: 0.0)

Tests/CodeEditTextViewTests/TextLayoutManagerTests.swift

@@ -0,0 +1,102 @@
+import Testing
+import AppKit
+@testable import CodeEditTextView
+
+extension TextLineStorage {
+    /// Validate that the internal tree is intact and correct.
+    ///
+    /// Ensures that:
+    /// - All lines can be queried by their index starting from `0`.
+    /// - All lines can be found by iterating `y` positions.
+    func validateInternalState() {
+        func validateLines(_ lines: [TextLineStorage<Data>.TextLinePosition]) {
+            var _lastLine: TextLineStorage<Data>.TextLinePosition?
+            for line in lines {
+                guard let lastLine = _lastLine else {
+                    #expect(line.index == 0)
+                    _lastLine = line
+                    return
+                }
+
+                #expect(line.index == lastLine.index + 1)
+                #expect(line.yPos >= lastLine.yPos + lastLine.height)
+                #expect(line.range.location == lastLine.range.max + 1)
+                _lastLine = line
+            }
+        }
+
+        let linesUsingIndex = (0..<count).compactMap({ getLine(atIndex: $0) })
+        validateLines(linesUsingIndex)
+
+        let linesUsingYValue = Array(linesStartingAt(0, until: height))
+        validateLines(linesUsingYValue)
+    }
+}
+
+@Suite
+@MainActor
+struct TextLayoutManagerTests {
+    let textView: TextView
+    let textStorage: NSTextStorage
+    let layoutManager: TextLayoutManager
+
+    init() throws {
+        textView = TextView(string: "A\nB\nC\nD")
+        textStorage = textView.textStorage
+        layoutManager = try #require(textView.layoutManager)
+    }
+
+    @Test(
+        arguments: [
+            ("\nE", NSRange(location: 6, length: 0), 5),
+            ("0\n", NSRange(location: 0, length: 0), 5), // at beginning
+            ("A\nBC\nD", NSRange(location: 3, length: 0), 6), // in middle
+            ("A\r\nB\nC\rD", NSRange(location: 0, length: 0), 7) // Insert mixed line breaks
+        ]
+    )
+    func insertText(_ testItem: (String, NSRange, Int)) throws { // swiftlint:disable:this large_tuple
+        let (insertText, insertRange, lineCount) = testItem
+
+        textStorage.replaceCharacters(in: insertRange, with: insertText)
+
+        #expect(layoutManager.lineCount == lineCount)
+        #expect(layoutManager.lineStorage.length == textStorage.length)
+        layoutManager.lineStorage.validateInternalState()
+    }
+
+    @Test(
+        arguments: [
+            (NSRange(location: 5, length: 2), 3), // At end
+            (NSRange(location: 0, length: 2), 3), // At beginning
+            (NSRange(location: 2, length: 3), 3) // In middle
+        ]
+    )
+    func deleteText(_ testItem: (NSRange, Int)) throws {
+        let (deleteRange, lineCount) = testItem
+
+        textStorage.deleteCharacters(in: deleteRange)
+
+        #expect(layoutManager.lineCount == lineCount)
+        #expect(layoutManager.lineStorage.length == textStorage.length)
+        layoutManager.lineStorage.validateInternalState()
+    }
+
+    @Test(
+        arguments: [
+            ("\nD\nE\nF", NSRange(location: 5, length: 2), 6), // At end
+            ("A\nY\nZ", NSRange(location: 0, length: 1), 6), // At beginning
+            ("1\n2\n", NSRange(location: 2, length: 4), 4), // In middle
+            ("A\nB\nC\nD\nE\nF\nG", NSRange(location: 0, length: 7), 7), // Entire string
+            ("A\r\nB\nC\r", NSRange(location: 0, length: 6), 4) // Mixed line breaks
+        ]
+    )
+    func replaceText(_ testItem: (String, NSRange, Int)) throws { // swiftlint:disable:this large_tuple
+        let (replaceText, replaceRange, lineCount) = testItem
+
+        textStorage.replaceCharacters(in: replaceRange, with: replaceText)
+
+        #expect(layoutManager.lineCount == lineCount)
+        #expect(layoutManager.lineStorage.length == textStorage.length)
+        layoutManager.lineStorage.validateInternalState()
+    }
+}