Add tests to NIAttributedLabel for ensuring that accessibleElements h…

…ave the correct frames under different link orderings whether merging multiline links or not. This file is still missing a lot of coverage but this is a good start. PiperOrigin-RevId: 560782099
Mu-L · Aug 28, 2023 · fd5143a · fd5143a
1 parent 1e03c49
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Showing 3 changed files with 193 additions and 39 deletions.
diff --git a/src/attributedlabel/src/NIAttributedLabel.h b/src/attributedlabel/src/NIAttributedLabel.h
@@ -68,6 +68,45 @@ typedef NS_ENUM(NSInteger, NILinkOrdering) {
 extern NSString* const NIAttributedLabelLinkAttributeName; // Value is an NSTextCheckingResult.
 
 @protocol NIAttributedLabelDelegate;
+/**
+ * @internal
+ *
+ * The NIViewAccessibilityElement class encapsulates information about an item
+ * that should be accessible to users with disabilities, but isn't accessible
+ * by default and might be used in animations.
+ *
+ * Differences between UIAccessibilityElement and NIViewAccessibilityElement:
+ *
+ * - The accessibilityContainer must be a UIView.
+ * - The accessibilityFrame is recomputed every time from the frameInContainer
+ *   and the accessibilityContainer.
+ * - The accessibilityPath and accessibilityActivationPoint (if applicable) are
+ *   recomputed every time from the pointsInContainer and the accessibilityContainer.
+ *
+ * These differences cease to be as soon as the initial accessibility container
+ * is changed externally, which is internally tracked by isContainerValid.
+ */
+@interface NIViewAccessibilityElement : UIAccessibilityElement
+
+- (instancetype)initWithAccessibilityContainer:(id)container
+                              frameInContainer:(CGRect)frameInContainer
+                             pointsInContainer:(NSArray *)pointsInContainer;
+
+- (instancetype)initWithAccessibilityContainer:(id)container
+                              frameInContainer:(CGRect)frameInContainer;
+
+// This frame is in the accessibilityContainer coordinates.
+@property(nonatomic, readonly) CGRect frameInContainer;
+
+// The first element of the array is the accessibilityActivationPoint, the rest of the array is the
+// accessibilityPath.
+@property(nonatomic, readonly) NSArray<NSValue*> *pointsInContainer;
+
+/// If set to @c YES, this element remembers the last valid accessibility container when it receives
+/// a new one.
+@property(nonatomic) BOOL rememberLastValidContainer;
+
+@end
 
 /**
  * The NIAttributedLabel class provides support for displaying rich text with selectable links and
@@ -179,6 +218,7 @@ extern NSString* const NIAttributedLabelLinkAttributeName; // Value is an NSText
 - (void)insertImage:(UIImage *)image atIndex:(NSInteger)index margins:(UIEdgeInsets)margins verticalTextAlignment:(NIVerticalTextAlignment)verticalTextAlignment;
 
 - (void)invalidateAccessibleElements;
+- (NSArray *)accessibleElements;
 
 - (NSTextCheckingResult *)linkAtPoint:(CGPoint)point;
 

diff --git a/src/attributedlabel/src/NIAttributedLabel.m b/src/attributedlabel/src/NIAttributedLabel.m
@@ -124,44 +124,6 @@ CGSize NISizeOfAttributedStringConstrainedToSize(NSAttributedString* attributedS
   return CGSizeMake(NICGFloatCeil(newSize.width), NICGFloatCeil(newSize.height));
 }
 
-/**
- * @internal
- *
- * The NIViewAccessibilityElement class encapsulates information about an item
- * that should be accessible to users with disabilities, but isn't accessible
- * by default and might be used in animations.
- *
- * Differences between UIAccessibilityElement and NIViewAccessibilityElement:
- *
- * - The accessibilityContainer must be a UIView.
- * - The accessibilityFrame is recomputed every time from the frameInContainer
- *   and the accessibilityContainer.
- * - The accessibilityPath and accessibilityActivationPoint (if applicable) are
- *   recomputed every time from the pointsInContainer and the accessibilityContainer.
- *
- * These differences cease to be as soon as the initial accessibility container
- * is changed externally, which is internally tracked by isContainerValid.
- */
-@interface NIViewAccessibilityElement : UIAccessibilityElement
-
-- (instancetype)initWithAccessibilityContainer:(id)container
-                              frameInContainer:(CGRect)frameInContainer
-                             pointsInContainer:(NSArray *)pointsInContainer;
-
-- (instancetype)initWithAccessibilityContainer:(id)container frameInContainer:(CGRect)frameInContainer;
-
-// This frame is in the accessibilityContainer coordinates.
-@property (nonatomic, readonly) CGRect frameInContainer;
-
-// The first element of the array is the accessibilityActivationPoint, the rest of the array is the
-// accessibilityPath.
-@property (nonatomic, readonly) NSArray *pointsInContainer; // of NSValue
-
-/// If set to @c YES, this element remembers the last valid accessibility container when it receives
-/// a new one.
-@property(nonatomic) BOOL rememberLastValidContainer;
-
-@end
 
 @interface NIViewAccessibilityElement ()
 
@@ -1201,6 +1163,7 @@ - (NIViewAccessibilityElement *)accessibilityElementForRange:(NSRange)range {
     return nil;
   }
 
+  // Calculate multiline link bounds using boundsForRects.
   CGRect bounds = [self boundsForRects:rects];
   CGRect firstRect = [[rects firstObject] CGRectValue];
   // The activation point can be any point in the area. Let's make it the center of the first small

diff --git a/src/attributedlabel/unittests/NIAttributedLabelTests.m b/src/attributedlabel/unittests/NIAttributedLabelTests.m
@@ -16,10 +16,11 @@
 
 // See: http://bit.ly/hS5nNh for unit test macros.
 
+#import "NimbusAttributedLabel.h"
+
 #import <Foundation/Foundation.h>
 #import <XCTest/XCTest.h>
 
-#import "NimbusAttributedLabel.h"
 #import "NIAttributedLabel+Testing.h"
 
 @interface NIAttributedLabelTestMonitor : NSObject <NIAttributedLabelDelegate>
@@ -58,6 +59,25 @@ @interface NIAttributedLabelTests : XCTestCase
 
 @implementation NIAttributedLabelTests
 
++ (NIAttributedLabel *)makeGenericMultilineLabelWithFrame:(CGRect)frame {
+  // Create an attributed string with a link.
+  NSString *string = @"Unlinked content. Linked content.\nLinked content. Unlinked content.";
+  NSURL *URL = [NSURL URLWithString:@"http://youtube.com"];
+  NSTextCheckingResult *textCheckingResult =
+      [NSTextCheckingResult linkCheckingResultWithRange:NSMakeRange(18, 32) URL:URL];
+  NSDictionary<NSAttributedStringKey, id> *attributes =
+      @{NIAttributedLabelLinkAttributeName : textCheckingResult};
+  NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:string
+                                                                       attributes:attributes];
+
+  // Create a label.
+  NIAttributedLabel *label = [[NIAttributedLabel alloc] initWithFrame:frame];
+  label.attributedText = attributedText;
+  label.numberOfLines = 0;
+
+  return label;
+}
+
 - (void)testLongPressCallbackOverridesActionSheetCallbackWhenTouchingLink {
   // Create an attributed string with a link.
   NSString *string = @"NimbusKit";
@@ -109,4 +129,135 @@ - (void)testActionSheetCallbackDeliveredWhenTouchingLink {
   XCTAssertEqual(monitor.actionSheetCallbackCount, 1);
 }
 
+- (void)testPreOrderedLinks {
+  CGRect labelFrame = CGRectMake(0,0,200,200);
+  NIAttributedLabel *label = [NIAttributedLabelTests makeGenericMultilineLabelWithFrame:labelFrame];
+
+  // Create pre-order non-merged multiline links.
+  label.linkOrdering = NILinkOrderingFirst;
+  label.shouldMergeMultilineLinks = NO;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleElements =
+      [label.accessibleElements copy];
+
+  // Given labelFrame (0,0,200), expect {(96, 3, 81, 12),(0, 18, 85, 12),(0,0,200,200)}.
+  CGRect firstFrame = [accessibleElements objectAtIndex:0].frameInContainer;
+  CGRect secondFrame = [accessibleElements objectAtIndex:1].frameInContainer;
+  // Test second frame starts at start of labelFrame.
+  XCTAssertEqual(secondFrame.origin.x, labelFrame.origin.x);
+  // Test first frame starts after second frame.
+  XCTAssertGreaterThan(firstFrame.origin.x,secondFrame.origin.x);
+  // Test first frame start above second frame.
+  XCTAssertLessThan(firstFrame.origin.y,secondFrame.origin.y);
+  // Test both frames have the same height (same attribute).
+  XCTAssertEqual(firstFrame.size.height,secondFrame.size.height);
+  // Test last element is labelFrame.
+  XCTAssertTrue(CGRectEqualToRect([accessibleElements objectAtIndex:2].frameInContainer, labelFrame));
+
+  // Create pre-order merged multiline links.
+  [label invalidateAccessibleElements];
+  label.shouldMergeMultilineLinks = YES;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleMergedElements =
+      [label.accessibleElements copy];
+
+  // Given labelFrame (0,0,200), expect {(0, 3, 177, 27),(0,0,200,200)}.
+  CGRect mergedFrame = [accessibleMergedElements objectAtIndex:0].frameInContainer;
+  // Test first frame starts at start of labelFrame.
+  XCTAssertEqual(mergedFrame.origin.x, labelFrame.origin.x);
+  // Test last element is labelFrame.
+  XCTAssertTrue(CGRectEqualToRect([accessibleMergedElements objectAtIndex:1].frameInContainer,
+                                  labelFrame));
+
+  // Test pre-order non-merged multiline link frames union to merged multiline link frame.
+  XCTAssertTrue(
+      CGRectEqualToRect(CGRectUnion(firstFrame, secondFrame), mergedFrame));
+}
+
+- (void)testPostOrderedLinks {
+  CGRect labelFrame = CGRectMake(0,0,200,200);
+  NIAttributedLabel *label = [NIAttributedLabelTests makeGenericMultilineLabelWithFrame:labelFrame];
+
+  // Create post-order non-mergegd multiline links.
+  label.linkOrdering = NILinkOrderingLast;
+  label.shouldMergeMultilineLinks = NO;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleElements =
+      [label.accessibleElements copy];
+
+  // Given labelFrame (0,0,200), expect {(0,0,200,200),(96, 3, 81, 12),(0, 18, 85, 12)}.
+  CGRect firstFrame = [accessibleElements objectAtIndex:1].frameInContainer;
+  CGRect secondFrame = [accessibleElements objectAtIndex:2].frameInContainer;
+  // Test first frame is labelFrame.
+  XCTAssertTrue(CGRectEqualToRect([accessibleElements objectAtIndex:0].frameInContainer, labelFrame));
+  // Test second frame starts at start of labelFrame.
+  XCTAssertEqual(secondFrame.origin.x, labelFrame.origin.x);
+  // Test first frame starts after second frame.
+  XCTAssertGreaterThan(firstFrame.origin.x,secondFrame.origin.x);
+  // Test first frame start above second frame.
+  XCTAssertLessThan(firstFrame.origin.y,secondFrame.origin.y);
+  // Test both frames have the same height (same attribute).
+  XCTAssertEqual(firstFrame.size.height,secondFrame.size.height);
+
+  // Create post-order merged multiline links.
+  [label invalidateAccessibleElements];
+  label.shouldMergeMultilineLinks = YES;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleMergedElements =
+      [label.accessibleElements copy];
+
+  // Test first frame is labelFrame.
+  XCTAssertTrue(CGRectEqualToRect([accessibleMergedElements objectAtIndex:0].frameInContainer,
+                                  labelFrame));
+  // Given labelFrame (0,0,200), expect {(0,0,200,200),(0, 3, 177, 27)}.
+  CGRect mergedFrame = [accessibleMergedElements objectAtIndex:1].frameInContainer;
+  // Test first frame starts at start of labelFrame.
+  XCTAssertEqual(mergedFrame.origin.x, labelFrame.origin.x);
+
+  // Test post-order non-merged multiline links union to merged multiline link.
+  XCTAssertTrue(
+      CGRectEqualToRect(CGRectUnion(firstFrame, secondFrame), mergedFrame));
+}
+
+- (void)testInOrderLinks {
+  CGRect labelFrame = CGRectMake(0,0,200,200);
+  NIAttributedLabel *label = [NIAttributedLabelTests makeGenericMultilineLabelWithFrame:labelFrame];
+
+  // Links in-order non-merged multiline links.
+  label.linkOrdering = NILinkOrderingOriginal;
+  label.shouldMergeMultilineLinks = NO;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleElements =
+      [label.accessibleElements copy];
+
+  // Given labelFrame (0,0,200), expect {(0, 3, 96, 12),(0, 3, 177, 27),(85, 18, 93, 12)}.
+  CGRect firstFrame = [accessibleElements objectAtIndex:0].frameInContainer;
+  CGRect mergedFrame = [accessibleElements objectAtIndex:1].frameInContainer;
+  CGRect secondFrame = [accessibleElements objectAtIndex:2].frameInContainer;
+  // Test first frame starts at start of labelFrame.
+  XCTAssertEqual(firstFrame.origin.x, labelFrame.origin.x);
+  // Test first frame has same origin as merged frame.
+  XCTAssertTrue(CGPointEqualToPoint(firstFrame.origin, mergedFrame.origin));
+  // Test first frame has smaller width than merged frame.
+  XCTAssertLessThan(firstFrame.size.width, mergedFrame.size.width);
+  // Test first frame has smaller height than merged frame.
+  XCTAssertLessThan(firstFrame.size.height, mergedFrame.size.height);
+
+  // Test first frame start above second frame.
+  XCTAssertLessThan(firstFrame.origin.y, secondFrame.origin.y);
+  // Test second frame has smaller width than merged frame.
+  XCTAssertLessThan(secondFrame.size.width, mergedFrame.size.width);
+  // Test second frame has smaller height than merged frame.
+  XCTAssertLessThan(secondFrame.size.height, mergedFrame.size.height);
+  // Test first and second frames have the same height (same attribute).
+  XCTAssertEqual(firstFrame.size.height,secondFrame.size.height);
+
+  // Links in-order merged multiline links.
+  [label invalidateAccessibleElements];
+  label.shouldMergeMultilineLinks = YES;
+  NSMutableArray<NIViewAccessibilityElement *> *accessibleMergedElements =
+      [label.accessibleElements copy];
+
+  for (int frameIndex = 0; frameIndex < accessibleMergedElements.count; frameIndex++) {
+    XCTAssertTrue(
+        CGRectEqualToRect([accessibleElements objectAtIndex:frameIndex].frameInContainer,
+                          [accessibleMergedElements objectAtIndex:frameIndex].frameInContainer));
+  }
+}
+
 @end