Fix extra line breaks being inserted before lists

Sources/HTMLStreamer/AttributedStringConverter.swift

@@ -28,6 +28,7 @@ public struct AttributedStringConverter<Callbacks: HTMLConversionCallbacks> {
     private var styleStack: [Style] = []
     private var previouslyFinishedBlockElement = false
     private var currentElementIsEmpty = true
+    private var previouslyFinishedListItem = false
     // The current run of text w/o styles changing
     private var currentRun: String = ""
     
@@ -135,7 +136,7 @@ public struct AttributedStringConverter<Callbacks: HTMLConversionCallbacks> {
             finishRun()
             styleStack.append(.unorderedList)
         case "li":
-            if str.length != 0 || !currentRun.isEmpty {
+            if previouslyFinishedListItem {
                 currentRun.append("\n")
             }
             let marker: String
@@ -186,12 +187,15 @@ public struct AttributedStringConverter<Callbacks: HTMLConversionCallbacks> {
             finishRun()
             removeLastStyle(.orderedList)
             finishBlockElement()
+            previouslyFinishedListItem = false
         case "ul":
             finishRun()
             removeLastStyle(.unorderedList)
             finishBlockElement()
+            previouslyFinishedListItem = false
         case "li":
             finishRun()
+            previouslyFinishedListItem = true
         default:
             break
         }

Tests/HTMLStreamerTests/AttributedStringConverterTests.swift

@@ -319,4 +319,19 @@ final class AttributedStringConverterTests: XCTestCase {
         XCTAssertEqual(convert("<p></p><blockquote><span>inside<br>quote</span></blockquote><span>after</span><p></p>"), result)
     }
     
+    func testParagraphFollowedByList() {
+        let result = NSMutableAttributedString()
+        result.append(NSAttributedString(string: "a\n\n", attributes: [
+            .font: font,
+            .paragraphStyle: NSParagraphStyle.default,
+            .foregroundColor: color,
+        ]))
+        result.append(NSAttributedString(string: "\t1.\tb\n\t2.\tc", attributes: [
+            .font: font,
+            .paragraphStyle: listParagraphStyle,
+            .foregroundColor: color,
+        ]))
+        XCTAssertEqual(convert("<p>a</p><ol><li>b</li><li>c</li></ol>"), result)
+    }
+    
 }