           XCTAssertNotNil(files["elon"])
         }
       }
-    } else {
-      XCTFail("resource needed for this test can't be found")
-    }
   }
 
   func testSendingAFileSpecifiedByDataWithoutMimetype() {

  }

  func testSendingAFileSpecifiedByURLWithoutMimetype() {
    if let elonPhotoURL = Bundle(for: JustSendingFiles.self)
      .url(forResource: "elon", withExtension: "jpg")
    {
      let r = Just.post("http://httpbin.org/post",
                        files: ["elon": .url(elonPhotoURL, nil)])
      XCTAssertNotNil(r.json)
      if let data = r.json as? [String: Any] {
        XCTAssertNotNil(data["files"])
        if let files = data["files"] as? [String: String] {
          XCTAssertNotNil(files["elon"])
        }
      }
    } else {
      XCTFail("resource needed for this test can't be found")
    }
  }

  func testSendingAFileSpecifiedByURLWithMimetype() {
    if let elonPhotoURL = Bundle(for: JustSendingFiles.self)
      .url(forResource: "elon", withExtension: "jpg")
    {
      let r = Just.post("http://httpbin.org/post",
                        files: ["elon": .url(elonPhotoURL, "image/jpeg")])
      XCTAssertNotNil(r.json)

}

final class JustSendingFiles: XCTestCase {
  private var elonPhotoURL: URL {
    let lastPathSegmentLength = #file.split(separator: "/").last!.count
    let parentLength = #file.count - lastPathSegmentLength
    let elonPhotoPath = String(#file.prefix(parentLength)) + "elon.jpg"
    return URL(fileURLWithPath: elonPhotoPath)
  }

  func testNotIncludeMultipartHeaderForEmptyFiles() {
    let r = Just.post("http://httpbin.org/post", files: [: ])
    XCTAssertNotNil(r.json)
