キャッチブロックをカバーする方法は？

Question

私のメソッドwriteList()の完全なコードカバレッジを持っていますが、キャッチブロックのカバー方法はわかりません。

私の方法は次のとおりです。私はあなただったら

public class ListOfNumbers { 


    //...another code... 


    public void writeList() { 
     try (FileOutputStream inputStream = new FileOutputStream(this.pathOut); 
       OutputStreamWriter outputStreamWriter = new OutputStreamWriter(inputStream); 
       PrintWriter out = new PrintWriter(outputStreamWriter)) { 
      for (int i = 0; i < this.numbers.size(); i++) { 
       out.println("Value at: " + i + " = " + this.numbers.get(i)); 
      } 
     } catch (final ArrayIndexOutOfBoundsException e) { 
      ListOfNumbers.LOGGER.error("Caught ArrayIndexOutOfBoundsException: " + e.getMessage(), 
        e); 
     } catch (final FileNotFoundException e) { 
      ListOfNumbers.LOGGER.error("Caught FileNotFoundException: " + e.getMessage(), e); 
     } catch (final IOException e) { 
      ListOfNumbers.LOGGER.error("Caught IOException: " + e.getMessage(), e); 
     } 
    } 

} 

Answer 1

は、それを行うには、私は別の方法にnumbersを記述したコードを移動することで、それはより多くのテスト可能にするために私のコードを書き換えるだろう、この新しいメソッドを模擬して、Mockitoを使用して必要なものをスローします。

だからあなたのコードは、そのようなことが考えられます。

public void writeList() { 
    try (FileOutputStream inputStream = new FileOutputStream(this.pathOut); 
      OutputStreamWriter outputStreamWriter = new OutputStreamWriter(inputStream); 
      PrintWriter out = new PrintWriter(outputStreamWriter)) { 
     // Delegate the way to write the numbers to this new method 
     writeNumbers(out); 
    } catch (final ArrayIndexOutOfBoundsException e) { 
     ListOfNumbers.LOGGER.error(
      "Caught ArrayIndexOutOfBoundsException: " + e.getMessage(), e 
     ); 
    } catch (final FileNotFoundException e) { 
     ListOfNumbers.LOGGER.error("Caught FileNotFoundException: " + e.getMessage(), e); 
    } catch (final IOException e) { 
     ListOfNumbers.LOGGER.error("Caught IOException: " + e.getMessage(), e); 
    } 
} 

/** 
* The new method that is protected here but could also be package protected 
* but cannot be private to be able to override it. 
*/ 
protected void writeNumbers(PrintWriter out) { 
    for (int i = 0; i < this.numbers.size(); i++) { 
     out.println("Value at: " + i + " = " + this.numbers.get(i)); 
    } 
} 

次に、あなたのユニットテストは、次のようになります。

@Test 
public void causeAIOException() { 
    ListOfNumbers lon = // Create your instance here 
    // Create a Spy to be able to mock the method writeNumbers 
    ListOfNumbers listOfNumbers = Mockito.spy(lon); 
    // This will make any call to writeNumbers throw a IOException 
    Mockito.doThrow(IOException.class).when(listOfNumbers) 
     .writeNumbers(Matchers.any(PrintWriter.class)); 
    // Call the method on the spy 
    listOfNumbers.writeList(); 
} 

NB：FileNotFoundExceptionの場合、あなたは、単に既存のフォルダを提供することができますnew FileOutputStreamがFileNotFoundExceptionを投げるケースの1つであるため、pathOutとなり、再生が容易です。

Answer 2

class ListOfNumbers { 

    public void writeList() throws ArrayIndexOutOfBoundsException,FileNotFoundException,IOException { 
     try (FileOutputStream inputStream = new FileOutputStream(this.pathOut); 
       OutputStreamWriter outputStreamWriter = new OutputStreamWriter(inputStream); 
       PrintWriter out = new PrintWriter(outputStreamWriter)) { 
      for (int i = 0; i < this.numbers.size(); i++) { 
       out.println("Value at: " + i + " = " + this.numbers.get(i)); 
      } 

    } 

} 


public class Main{ 
public static void main(String [] args){ 
    try{ 
    ListOfNumbers list=new ListOfNumbers(); 
try{ 
    list.writeList(); 
} 
    } catch (ArrayIndexOutOfBoundsException e) { 
      ListOfNumbers.LOGGER.error("Caught ArrayIndexOutOfBoundsException: " + e.getMessage(), 
        e); 
     } catch (FileNotFoundException e) { 
      ListOfNumbers.LOGGER.error("Caught FileNotFoundException: " + e.getMessage(), e); 
     } catch (IOException e) { 
      ListOfNumbers.LOGGER.error("Caught IOException: " + e.getMessage(), e); 
     }  

} 
} 
}