ComponentTextKitApplicationTests/CKTextKitTruncationTests.mm

/*
 *  Copyright (c) 2014-present, Facebook, Inc.
 *  All rights reserved.
 *
 *  This source code is licensed under the BSD-style license found in the
 *  LICENSE file in the root directory of this source tree. An additional grant
 *  of patent rights can be found in the PATENTS file in the same directory.
 *
 */

#import <Foundation/Foundation.h>
#import <XCTest/XCTest.h>

#import <ComponentTextKit/CKTextKitContext.h>
#import <ComponentTextKit/CKTextKitTailTruncater.h>

@interface CKTextKitTruncationTests : XCTestCase

@end

@implementation CKTextKitTruncationTests

- (NSString *)_sentenceString
{
  return @"90's cray photo booth tote bag bespoke Carles. Plaid wayfarers Odd Future master cleanse tattooed four dollar toast small batch kale chips leggings meh photo booth occupy irony.";
}

- (NSAttributedString *)_sentenceAttributedString
{
  return [[NSAttributedString alloc] initWithString:[self _sentenceString] attributes:@{}];
}

- (NSAttributedString *)_simpleTruncationAttributedString
{
  return [[NSAttributedString alloc] initWithString:@"..." attributes:@{}];
}

- (void)testEmptyTruncationStringSameAsStraightTextKitTailTruncation
{
  CGSize constrainedSize = CGSizeMake(100, 50);
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitContext *context = [[CKTextKitContext alloc] initWithAttributedString:attributedString
                                                                   lineBreakMode:NSLineBreakByWordWrapping
                                                            maximumNumberOfLines:0
                                                                 constrainedSize:constrainedSize
                                                            layoutManagerFactory:nil];
  __block NSRange textKitVisibleRange;
  [context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
    textKitVisibleRange = [layoutManager characterRangeForGlyphRange:[layoutManager glyphRangeForTextContainer:textContainer]
                                                    actualGlyphRange:NULL];
  }];
  CKTextKitTailTruncater *tailTruncater = [[CKTextKitTailTruncater alloc] initWithContext:context
                                                               truncationAttributedString:nil
                                                                   avoidTailTruncationSet:nil
                                                                          constrainedSize:constrainedSize];
  XCTAssert(NSEqualRanges(textKitVisibleRange, tailTruncater.visibleRanges[0]));
}

- (void)testSimpleTailTruncation
{
  CGSize constrainedSize = CGSizeMake(100, 60);
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitContext *context = [[CKTextKitContext alloc] initWithAttributedString:attributedString
                                                                   lineBreakMode:NSLineBreakByWordWrapping
                                                            maximumNumberOfLines:0
                                                                 constrainedSize:constrainedSize
                                                            layoutManagerFactory:nil];
  CKTextKitTailTruncater *tailTruncater = [[CKTextKitTailTruncater alloc] initWithContext:context
                                                               truncationAttributedString:[self _simpleTruncationAttributedString]
                                                                   avoidTailTruncationSet:[NSCharacterSet characterSetWithCharactersInString:@""]
                                                                          constrainedSize:constrainedSize];
  __block NSString *drawnString;
  [context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
    drawnString = textStorage.string;
  }];
  NSString *expectedString = @"90's cray photo booth tote bag bespoke Carles. Plaid wayfarers...";
  XCTAssertEqualObjects(expectedString, drawnString);
  XCTAssert(NSEqualRanges(NSMakeRange(0, 62), tailTruncater.visibleRanges[0]));
}

- (void)testAvoidedCharTailWordBoundaryTruncation
{
  CGSize constrainedSize = CGSizeMake(100, 50);
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitContext *context = [[CKTextKitContext alloc] initWithAttributedString:attributedString
                                                                   lineBreakMode:NSLineBreakByWordWrapping
                                                            maximumNumberOfLines:0
                                                                 constrainedSize:constrainedSize
                                                            layoutManagerFactory:nil];
  CKTextKitTailTruncater *tailTruncater = [[CKTextKitTailTruncater alloc] initWithContext:context
                                                               truncationAttributedString:[self _simpleTruncationAttributedString]
                                                                   avoidTailTruncationSet:[NSCharacterSet characterSetWithCharactersInString:@"."]
                                                                          constrainedSize:constrainedSize];
  (void)tailTruncater;
  __block NSString *drawnString;
  [context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
    drawnString = textStorage.string;
  }];
  // This should have removed the additional "." in the string right after Carles.
  NSString *expectedString = @"90's cray photo booth tote bag bespoke Carles...";
  XCTAssertEqualObjects(expectedString, drawnString);
}

- (void)testAvoidedCharTailCharBoundaryTruncation
{
  CGSize constrainedSize = CGSizeMake(50, 50);
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitContext *context = [[CKTextKitContext alloc] initWithAttributedString:attributedString
                                                                   lineBreakMode:NSLineBreakByCharWrapping
                                                            maximumNumberOfLines:0
                                                                 constrainedSize:constrainedSize
                                                            layoutManagerFactory:nil];
  CKTextKitTailTruncater *tailTruncater = [[CKTextKitTailTruncater alloc] initWithContext:context
                                                               truncationAttributedString:[self _simpleTruncationAttributedString]
                                                                   avoidTailTruncationSet:[NSCharacterSet characterSetWithCharactersInString:@"."]
                                                                          constrainedSize:constrainedSize];
  // So Xcode doesn't yell at me for an unused var...
  (void)tailTruncater;
  __block NSString *drawnString;
  [context performBlockWithLockedTextKitComponents:^(NSLayoutManager *layoutManager, NSTextStorage *textStorage, NSTextContainer *textContainer) {
    drawnString = textStorage.string;
  }];
  // This should have removed the additional "." in the string right after Carles.
  NSString *expectedString = @"90's cray photo booth t...";
  XCTAssertEqualObjects(expectedString, drawnString);
}

- (void)testHandleZeroHeightConstrainedSize
{
  CGSize constrainedSize = CGSizeMake(50, 0);
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitContext *context = [[CKTextKitContext alloc] initWithAttributedString:attributedString
                                                                   lineBreakMode:NSLineBreakByCharWrapping
                                                            maximumNumberOfLines:0
                                                                 constrainedSize:constrainedSize
                                                            layoutManagerFactory:nil];
  XCTAssertNoThrow([[CKTextKitTailTruncater alloc] initWithContext:context
                                        truncationAttributedString:[self _simpleTruncationAttributedString]
                                            avoidTailTruncationSet:[NSCharacterSet characterSetWithCharactersInString:@"."]
                                                   constrainedSize:constrainedSize]);
}

- (void)testNoLimitOfMaximumNumberOfLines
{
  const NSUInteger maximumNumberOfLines = 0;
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitRenderer *renderer = [[CKTextKitRenderer alloc]
                                 initWithTextKitAttributes:{
                                   .attributedString = attributedString,
                                   .maximumNumberOfLines = maximumNumberOfLines,
                                 }
                                 constrainedSize:CGSizeMake(50, INFINITY)];
  XCTAssertTrue(renderer.lineCount > maximumNumberOfLines);
}

- (void)testEnforcementOfMaximumNumberOfLines
{
  const NSUInteger maximumNumberOfLines = 3;
  NSAttributedString *attributedString = [self _sentenceAttributedString];
  CKTextKitRenderer *renderer = [[CKTextKitRenderer alloc]
                                 initWithTextKitAttributes:{
                                   .attributedString = attributedString,
                                   .maximumNumberOfLines = maximumNumberOfLines,
                                 }
                                 constrainedSize:CGSizeMake(50, INFINITY)];
  XCTAssertEqual(renderer.lineCount, maximumNumberOfLines);
}

@end