     
     XCTAssertTrue(numbers.asSequence().min() == 1)
     
-    let min: Int? = empty.asSequence().min()
+    let min: Int? = emptyNumbers.asSequence().min()
     XCTAssertTrue(min == nil)
     
   }

    
    XCTAssertTrue(numbers.asSequence().first() == 1)
    
    if let last = empty.asSequence().first() {
      XCTAssertTrue(false)
    } else {
      XCTAssertTrue(true)
    }
    
  }
  
  func testMap() {
    

    
    XCTAssertEqual(numbers.asSequence().filter( { $0 % 2 == 0} ).asArray(), [2, 4, 6, 8])
    
    XCTAssertTrue(emptyStrings.asSequence().filter( { $0.isEmpty } ).asArray().count == 0)
    
  }
  
