Add StrikethroughDoubleTildeTests

Author: hanny-ph

Tests/MarkdownTests/Parsing/StrikethroughDoubleTildeTests.swift

@@ -0,0 +1,30 @@
+//
+//  StrikethroughDoubleTildeTests.swift
+//
+//
+//  Created by Hanny Hariyadi Prastya on 2024/07/18.
+//
+
+@testable import Markdown
+import XCTest
+
+class StrikethroughDoubleTildeTests: XCTestCase {
+    /// Verify that only double tildes are parsed as strikethroughs
+    func testDoubleTildeStrikethrough() {
+        let text = """
+        This is a ~~strikethrough~~ example, but this is ~not~.
+        """
+        
+        let expectedDump = """
+        Document @1:1-1:56
+        └─ Paragraph @1:1-1:56
+           ├─ Text @1:1-1:11 "This is a "
+           ├─ Strikethrough @1:11-1:28
+           │  └─ Text @1:13-1:26 "strikethrough"
+           └─ Text @1:28-1:56 " example, but this is ~not~."
+        """
+        
+        let document = Document(parsing: text, source: nil, options: [.onlyParseStrikethroughDoubleTilde])
+        XCTAssertEqual(expectedDump, document.debugDescription(options: .printSourceLocations))
+    }
+}