add node update contents test

Author: tib

Tests/SwiftSgmlTests/NodeTests.swift

@@ -0,0 +1,35 @@
+//
+//  File.swift
+//  
+//
+//  Created by Tibor Bodecs on 2022. 02. 06..
+//
+
+import XCTest
+@testable import SwiftSgml
+
+final class NodeTests: XCTestCase {
+
+    func testNodeContents() {
+        final class FooTag: Tag {
+            init(_ contents: String? = nil) {
+                super.init(Node(type: .standard, name: "foo", contents: contents))
+            }
+            
+            func updateContents() -> Tag {
+                node.contents = "bar"
+                return self
+            }
+        }
+
+        
+        let doc = Document {
+            FooTag()
+                .updateContents()
+        }
+
+        XCTAssertEqual(DocumentRenderer().render(doc), """
+                            <foo>bar</foo>
+                            """)
+    }
+}