Add a test case

Author: gibachan

Tests/SwiftBasicFormatTest/BasicFormatTests.swift

@@ -342,7 +342,7 @@ final class BasicFormatTest: XCTestCase {
     )
   }
 
-  func testNodeHavingParentNode() {
+  func testSubTreeNode() {
     let decl: DeclSyntax = """
     func test() {
         print(1)
@@ -359,4 +359,25 @@ final class BasicFormatTest: XCTestCase {
       """
     )
   }
+
+  func testSubTreeNodeWithIndentedParentNode() {
+    let decl: DeclSyntax = """
+    struct X {
+        func test() {
+            print(1)
+        }
+    }
+    """
+
+    let body = decl.cast(StructDeclSyntax.self).memberBlock.members.first!.decl.cast(FunctionDeclSyntax.self).body!
+
+    assertFormatted(
+      source: body.formatted().description,
+      expected: """
+      {
+              print(1)
+          }
+      """
+    )
+  }
 }