Issue/fix crash on toggle quotes

Aztec/Classes/Extensions/NSMutableAttributedString+ReplaceOcurrences.swift

@@ -32,17 +32,19 @@ extension NSMutableAttributedString {
 
         assert(!replacementString.contains(stringToFind),
                "Allowing the replacement string to contain the original string would result in a ininite loop.")
-
-        let swiftUTF16Range = string.utf16.range(from: range)
+        let rangeDifference = (replacementString as NSString).length - (stringToFind as NSString).length
+        var swiftUTF16Range = string.utf16.range(from: range)
         var swiftRange = string.range(from: swiftUTF16Range)
-
         while let matchRange = string.range(of: stringToFind, options: [], range: swiftRange, locale: nil) {
             let matchNSRange = string.utf16NSRange(from: matchRange)
 
             replaceCharacters(in: matchNSRange, with: replacementString)
 
             // Since the new string may invalidate the initial swift range, we want to update it.
-            swiftRange = swiftRange.lowerBound ..< string.index(matchRange.lowerBound, offsetBy: replacementString.count)
+            // And because the string that backs the NSAttributeString will change after the replace we need to recalculate the index from scratch
+            let updatedRange = range.extendedRight(by: rangeDifference)
+            swiftUTF16Range = string.utf16.range(from: updatedRange)
+            swiftRange = string.range(from: swiftUTF16Range)
         }
     }
 }

AztecTests/Extensions/NSMutableAttributedStringReplaceOcurrencesTests.swift

@@ -88,4 +88,14 @@ class NSMutableAttributedStringReplaceOcurrencesTests: XCTestCase {
 
         XCTAssertEqual(newAttrString, NSAttributedString(string: "🌎💚💚😬💚🌎"))
     }
+
+    /// Tests that replacing ocurrences on the end of a range work correctly
+    ///
+    func testReplaceOcurrencesThatAreOnEndOfRange() {
+        let attrString = NSAttributedString(string: "Hello"+String(.paragraphSeparator)+"Amazing"+String(.paragraphSeparator)+"World"+String(.paragraphSeparator))
+        let newAttrString = NSMutableAttributedString(attributedString: attrString)
+        newAttrString.replaceOcurrences(of: String(.paragraphSeparator), with: String(.lineFeed), within: NSRange(location:6, length: 8))
+
+        XCTAssertEqual(newAttrString, NSAttributedString(string: "Hello"+String(.paragraphSeparator)+"Amazing"+String(.lineFeed)+"World"+String(.paragraphSeparator)))
+    }
 }

AztecTests/TextKit/TextViewTests.swift

@@ -1254,6 +1254,22 @@ class TextViewTests: XCTestCase {
         XCTAssertEqual(textView.text, Constants.sampleText0 + Constants.sampleText1 + String(.lineFeed) + String(.lineFeed))
     }
 
+    /// Verifies that toggling a Blockquote paragraph in the middle of paragraph does not crash system.    
+    ///
+    func testTogglingBlockquoteOnMiddleOfRangeDoesNotCrash() {
+        let initialQuote = """
+            <blockquote><strong>Quote One</strong></blockquote>
+            <blockquote><strong>Quote Two</strong></blockquote>
+            <blockquote><strong>Quote Three</strong></blockquote>
+        """
+        let textView = TextViewStub(withHTML: initialQuote)
+
+        textView.selectedTextRange = textView.textRange(from: textView.endOfDocument, to: textView.endOfDocument)
+        textView.toggleBlockquote(range: NSRange(location: 11, length: 0))
+
+        XCTAssertEqual(textView.text, "Quote One" + String(.paragraphSeparator)+"Quote Two"+String(.lineFeed)+"Quote Three")
+    }
+
 
     // MARK: - Pre