为核心 Java 应用程序编写 Junit 测试用例

Question

I have BMI calculator java applications and it can calculate BMI of user to know his/her current body weight, This program will use both Metric (kg/m) and Imperial (lb/in) BMI formula, and After getting the results, user will know his/her BMI category (underweight, obese, overweight or normal).

I need to write Junit test cases for this application, the source code of it is shown below. Can anyone help me to write Junit test cases for this class, please

    public class MainSrc {

    final static double KG_TO_LBS = 2.20462;
    final static double M_TO_IN = 39.3701;
    private static DecimalFormat TWO_DECIMAL_PLACES = new DecimalFormat(".##");

    public static void main(String[] args) {
        double height, weight;

        System.out.println("The BMI Calculator by iasjem");     
        System.out.println();

        Scanner askUser= new Scanner(System.in);

        System.out.println("What is your weight (kg)?");
        weight = askUser.nextDouble();

        System.out.println("What is your height (m)?");
        height = askUser.nextDouble();

        System.out.println();
        System.out.println("Your body weight is:");
        System.out.println("In Metric units: " + TWO_DECIMAL_PLACES.format(metricFormula(height, weight)) + " kg");
        System.out.println("In Imperial units: " + TWO_DECIMAL_PLACES.format(imperialFormula(height, weight)) + " lbs");
        System.out.println("As a result, you are " + getCategory(metricFormula(height, weight)));

        askUser.close();
        System.exit(0);
    }

    // THE METRIC FORMULA
    public static double metricFormula(double m, double kg) {
        double result=0;

        result = kg / (Math.pow(m, 2));

        return result;
    }

    // THE IMPERIAL FORMULA
    public static double imperialFormula(double m, double kg) {
        double result=0;
        // convert kg to lbs and m to in
        double lbs = Math.round(kg * KG_TO_LBS);
        double in = Math.round((m * M_TO_IN) *100);

        result = (lbs / (Math.pow((in/100), 2)))* 703;

        return result;
    }

    // THE BMI CATEGORIES
    public static String getCategory (double result) {
        String category;
        if (result < 15) {
            category = "very severely underweight";
        } else if (result >=15 && result <= 16) {
            category = "severely underweight";
        } else if (result >16 && result <= 18.5) {
            category = "underweight";
        } else if (result >18.5 && result <= 25) {
            category = "normal (healthy weight)";
        } else if (result >25 && result <= 30) {
            category = "overweight";
        } else if (result >30 && result <= 35) {
            category = "moderately obese";
        } else if (result >35 && result <= 40) {
            category = "severely obese";
        } else {
            category ="very severely obese";
        }
        return category;
    }
}

Answer 1

Looking at the code this is something that you can use a tool such as Diffblue Cover to generate tests for you. There is a free online version which will generate tests for this code, for example here are a couple of tests that are generated for the get category method:

  // Test written by Diffblue Cover.
  @Test
  public void getCategoryInputPositiveOutputNotNull6() {

    // Act and Assert result
    Assert.assertEquals("severely obese", MainSrc.getCategory(36.0));

  }

  // Test written by Diffblue Cover.
  @Test
  public void getCategoryInputPositiveOutputNotNull5() {

    // Act and Assert result
    Assert.assertEquals("very severely obese", MainSrc.getCategory(240.0));

  }

As mentioned in the comments. if you need more information about how to write unit tests for this code then please provide some specific examples of tests that you have written and aren't working.