Actually skip test on older OSes

.github/workflows/ci.yml

@@ -8,9 +8,6 @@ on:
     branches:
       - '**'
 
-env:
-  DEVELOPER_DIR: /Applications/Xcode_13.2.app/Contents/Developer
-
 jobs:
   test:
     name: Test

RearrangeTests/NSTextRangeTests.swift

@@ -7,20 +7,23 @@ import UIKit
 
 #if os(macOS) || os(iOS) || os(tvOS)
 
-@available(iOS 15.0, macOS 12.0, tvOS 15.0, *)
 class NSTextRangeTests: XCTestCase {
-    func testFullDocumentRange() {
-        let content = NSTextContentStorage()
+    func testFullDocumentRange() throws {
+        if #available(iOS 15.0, macOS 12.0, tvOS 15.0, *) {
+            let content = NSTextContentStorage()
 
-        content.attributedString = NSAttributedString(string: "abcdef")
+            content.attributedString = NSAttributedString(string: "abcdef")
 
-        let range = NSRange(content.documentRange, provider: content)
+            let range = NSRange(content.documentRange, provider: content)
 
-        XCTAssertEqual(range, NSRange(0..<6))
+            XCTAssertEqual(range, NSRange(0..<6))
 
-        let textRange = NSTextRange(NSRange(0..<6), provider: content)
+            let textRange = NSTextRange(NSRange(0..<6), provider: content)
 
-        XCTAssertEqual(textRange, content.documentRange)
+            XCTAssertEqual(textRange, content.documentRange)
+        } else {
+            throw XCTSkip()
+        }
     }
 }