text: 
  describe("Calculator Minus", function() {
      var Calculator;
  
      beforeEach(function() {
          Calculator = require('../index');
      });
  
      describe("When subtracting a given value from the initial value", function() { 
  
          it("should accept two positive Numbers and return the expected subtraction", function() {
              var initialValue = 4;
              var userValue = 5;
              var total = initialValue - userValue;
              var result = Calculator(initialValue).minus(userValue);
              expect(result).toEqual(total);
          });
  
          it("should accept a positive and negative Number and return the expected subtraction", function() {
              var initialValue = -4;
              var userValue = 5;
              var total = initialValue - userValue;
              var result = Calculator(initialValue).minus(userValue);
              expect(result).toEqual(total);
          });
  
          it("should accept a two negative Numbers and return the expected subtraction", function() {
              var initialValue = -4;
              var userValue = -5;
              var total = initialValue - userValue;
              var result = Calculator(initialValue).minus(userValue);
              expect(result).toEqual(total);
          });
  
          it("should throw an error if the second value is a String", function() {
              var initialValue = -4;
              var nanValue = "1";
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a Object", function() {
              var initialValue = -4;
              var nanValue = { value: 1 };
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a Array", function() {
              var initialValue = 4;
              var nanValue = [1, 2];
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a Boolean", function() {
              var initialValue = 4;
              var nanValue = true;
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a NaN", function() {
              var initialValue = 4;
              var nanValue = NaN;
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a Null", function() {
              var initialValue = 4;
              var nanValue = null;
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
          it("should throw an error if the second value is a Undefined", function() {
              var initialValue = 4;
              var nanValue = undefined;
              expect(()=>{
                  Calculator(initialValue).minus(nanValue);
              }).toThrow();
          });
  
      });
  
  });