茉莉花不能读取未定义的属性'长度'

Question

你好我是一个新手到单元测试我写了一个程序，它需要3个参数两个romanletters和一个操作符（+， - ，/，*）它应该执行操作，它应该返回在romanLetters的价值是试图编写一个单元测试的问题，它说不能读取未定义的属性长度我不知道为什么发生我的代码运行良好，虽然。附上我在这里的代码

Mainjs文件

var main=function(operand1,operand2,operator) { 
    var concat,number; 
    var operand1=romantonumerals(operand1); 
    var operand2=romantonumerals(operand2); 
    //var operator=operatorconversion(operator); 
    console.log("operand1 "+operand1); 
    console.log("operand2 "+operand2); 
    if(operand1>operand2) { 
     concat=operand1+operator+operand2; 
    } 
    else { 
     concat=operand2+operator+operand1; 
    } 
    number=Math.round(eval(concat)); 
    console.log(number); 
    if(number<500) { 
     result=numeralstoroman(number) 
    } 
    else if(number===0) { 
     result="Make sure its greater than 0"; 
    } 
    else { 
     result="Make sure your number gets less than 500 try with some other romans"; 
    } 
    console.log(result); 
    return result; 
    }; 
    var numeralstoroman=function(number) { 
    var roman="",temp; 
    var ones=function(number) { 
     switch (number) { 
     case 1: 
      roman+="I"; 
      break; 
     case 2: 
      roman+="II"; 
      break; 
     case 3: 
      roman+="III"; 
      break; 
     case 4: 
      roman+="IV"; 
      break; 
     case 5: 
      roman+="V"; 
      break; 
     case 6: 
      roman+="VI"; 
      break; 
     case 7: 
      roman+="VII"; 
      break; 
     case 8: 
      roman+="VIII"; 
      break; 
     case 9: 
      roman+="IX"; 
      break; 
     } 
    }; 
    var twos=function(number) { 
     if(number>=10 && number<20) { 
     roman+="X"; 
     ones(number%10); 
     } 
     else if(number>=20 && number30) { 
     roman+="XX"; 
     ones(number%10); 
     } 
     else if(number>=30 && number<40) { 
     roman+="XXX"; 
     ones(number%10); 
     } 
     else if(number>=40 && number<50) { 
     roman+="XL"; 
     ones(number%10); 
     } 
     else if(number>=50 && number<60) { 
     roman+="L"; 
     ones(number%10); 
     } 
     else if(number>=60 && number<70) { 
     roman+="LX"; 
     ones(number%10); 
     } 
     else if(number>=70 && number<80) { 
     roman+="LXX"; 
     ones(number%10); 
     } 
     else if(number>=80 && number<90) { 
     roman+="LXXX"; 
     ones(number%10); 
     } 
     else if(number>=90 && number<100) { 
     roman+="XC"; 
     ones(number%10); 
     } 
    }; 
    var threes=function(number) { 
     if(number>=100 && number<200) { 
      roman+="C"; 
      if(number%100<10) { 
      ones(number%10); 
      } 
      else { 
      twos(number%100); 
      } 
     } 
     else if(number>=200 && number<300) { 
      roman+="CC"; 
      if(number%100<10) { 
      ones(number%10); 
      } 
      else { 
      twos(number%100); 
      } 
     } 
     else if(number>=300 && number<400) { 
      roman+="CCC"; 
      if(number%100<10) { 
      ones(number%10); 
      } 
      else { 
      twos(number%100); 
      } 
     } 
     else if(number>=400 && number<500) { 
      roman+="CD"; 
      if(number%100<10) { 
      ones(number%10); 
      } 
      else { 
      twos(number%100); 
      } 
     } 
    } 
    if(number<10) { 
     ones(number); 
    } 
    else if(number>=10 && number<100) { 
     twos(number); 
    } 
    else if(number>=100 && number<500) { 
     threes(number); 
    } 
    console.log(roman); 
    return roman; 
    }; 
    var character=function(str) { 
    switch(str) { 
     case "I": 
     return 1 
     case "V": 
     return 5 
     case "X": 
     return 10 
     case "L": 
     return 50 
     case "C": 
     return 100 
     case "D": 
     return 500 
     default: 
     return -1; 
    } 
    } 
    var romantonumerals=function(operand) { 
    var no=0,i=0,char1="",char2=""; 
    while(i<operand.length) { 
     char1=character(operand[i]); 
     if(i+1<operand.length) { 
     char2=character(operand[i+1]); 
     if(char1>=char2) { 
      no+=char1; 
      i++; 
     } 
     else { 
      no=no+(char2-char1); 
      i+=2; 
     } 
     } 
     else { 
     no+=char1; 
     i++; 
     } 
    } 
    return no; 
    }; 
    var ans=main("V","I","+"); 
    console.log(ans); 

JasmineHTML文件

<!DOCTYPE html> 
    <html> 
    <head> 
    <meta charset="utf-8"> 
    <title>Jasmine Spec Runner v2.2.0</title> 

    <link rel="shortcut icon" type="image/png" href="lib/jasmine-2.2.0/jasmine_favicon.png"> 
    <link rel="stylesheet" href="lib/jasmine-2.2.0/jasmine.css"> 

    <script src="lib/jasmine-2.2.0/jasmine.js"></script> 
    <script src="lib/jasmine-2.2.0/jasmine-html.js"></script> 
    <script src="lib/jasmine-2.2.0/boot.js"></script> 

    <!-- include source files here... --> 
    <script src="romtantonumeralstoroman.js"></script> 
    <!-- include spec files here... --> 
    <script src="spec.js"></script> 


    </head> 

    <body> 
    </body> 
    </html> 

茉莉花测试文件

describe("A suite", function() { 
it("contains spec with an expectation", function() { 
    main(); 
    expect(main("V","I","+").toBe("VI")); 
}); 
}); 

的jsfiddle链接

https://jsfiddle.net/pLecneto/

Answer 1

问题是你打电话main();没有任何参数在您的规范。如果操作数是undefined，则在while(i<operand.length)上抛出异常。

，改变你的expect声明，如：

expect(main("V","I","+")).toBe("VI");