Probably redundant tests, but why not

Tests/PathTests/PathTests.swift

@@ -653,6 +653,12 @@ class PathTests: XCTestCase {
             XCTAssertEqual(bar.type, .symlink)
         }
     }
+    
+    func testOptionalInitializer() throws {
+        XCTAssertNil(Path(""))
+        XCTAssertNil(Path("./foo"))
+        XCTAssertEqual(Path("/foo"), Path.root.foo)
+    }
 }
 
 private func XCTAssertEqual<P: Pathish, Q: Pathish>(_ p: P, _ q: Q, file: StaticString = #file, line: UInt = #line) {

Tests/PathTests/XCTestManifests.swift

@@ -46,6 +46,7 @@ extension PathTests {
         ("testMoveInto", testMoveInto),
         ("testMoveTo", testMoveTo),
         ("testNoUndesiredSymlinkResolution", testNoUndesiredSymlinkResolution),
+        ("testOptionalInitializer", testOptionalInitializer),
         ("testPathComponents", testPathComponents),
         ("testReadlinkOnFileReturnsSelf", testReadlinkOnFileReturnsSelf),
         ("testReadlinkOnNonExistantFileThrows", testReadlinkOnNonExistantFileThrows),