test: add unit tests for filterQuestionsByDifficulty and averageDifficulty methods

Author: ross-u

tests/quiz.spec.js

@@ -254,70 +254,32 @@ describe("Quiz", () => {
     });
   });
 
-  // ****************************************************************************************************
-  // DAY 2
-  //
-  // The 1st test is already written for you -  checking if the 'filter()' array method is used.
-  //
-  // The test block below is currently skipped ('xdescribe').
-  // Once you start working on the tests, change the 'xdescribe' to 'describe' to enable the tests.
-  // ****************************************************************************************************
-
-  xdescribe("filterQuestionsByDifficulty() method", () => {   
-    it("should use the 'filter()' array method on the 'questions' array", () => {
+  describe("filterQuestionsByDifficulty() method", () => {
+    it("should be defined", () => {
       // Instantiate a new Quiz object
       const quiz = new Quiz([], "test", 60);
-      // Set up a spy on the 'filter()' array method to track calls to it
-      const filterSpy = spyOn(quiz.questions, "filter");
-
-      // Call the 'filterQuestionsByDifficulty()' method
-      quiz.filterQuestionsByDifficulty(1);
-
-      // Check if the 'filter()' array method was called on the 'questions' array
-      expect(filterSpy).toHaveBeenCalled();
-      // Check that the 'filter()' array method was called only once
-      expect(filterSpy).toHaveBeenCalledTimes(1);
-      // Check that the 'filter()' array method was called correctly, with a function as its argument
-      expect(filterSpy).toHaveBeenCalledWith(jasmine.any(Function));
-    });    
-
-
-    // ****************************************************************************************************
-    // DAY 2: 'filterQuestionsByDifficulty()' method
-    //      
-    // Below are 4 tests that you need to write for the 'filterQuestionsByDifficulty()' method.
-    // ****************************************************************************************************
-
-
-    it("should be defined", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
-
-      // 2. Check if the filterQuestionsByDifficulty() method is defined
+      // Check if the filterQuestionsByDifficulty() method is defined
+      expect(quiz.filterQuestionsByDifficulty).toBeDefined();
 
     });
 
     it("should be a function", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
+      // Instantiate a new Quiz object
+      const quiz = new Quiz([], "test", 60);
+      // Check if the filterQuestionsByDifficulty() is a function
+      expect(typeof quiz.filterQuestionsByDifficulty).toBe("function");
 
-      // 2. Check if the .filterQuestionsByDifficulty is a function
     });
 
     it("should receive 1 argument (difficulty)", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
-
-      // 2. Check if the filterQuestionsByDifficulty() method takes 1 argument
+      // Instantiate a new Quiz object
+      const quiz = new Quiz([], "test", 60);      
+      // Check if the filterQuestionsByDifficulty() method takes 1 argument
+      expect(quiz.filterQuestionsByDifficulty.length).toEqual(1);
 
     });
 
     it("should update the 'questions' array with the questions filtered by difficulty", () => {
-      // 1. Read the above test description to understand what this test should do
-
       // Array with questions to be used in the test and passed to the Quiz constructor
       const questions = [
         {
@@ -346,19 +308,17 @@ describe("Quiz", () => {
         },
       ];
 
-      // YOUR CODE HERE:
-      //
-      // 2. Instantiate a new Quiz object with the test questions
+      // Instantiate a new Quiz object with the test questions
+      const quiz = new Quiz(questions, "test", 60);      
 
-      // 3. Call the `filterQuestionsByDifficulty()` method with a number between 1 and 3 as a 1st argument.
+      // Call the `filterQuestionsByDifficulty()` method with a number between 1 and 3 as a 1st argument.
+      quiz.filterQuestionsByDifficulty(2);
 
-      // 4. Check if the questions array has been filtered correctly
+      // Check if the questions array has been filtered correctly
+      expect(quiz.questions).toEqual([questions[1], questions[2]]);
     });
 
     it("should not change the 'questions' array if the 1st argument is not a number between 1 and 3", () => {
-      // 1. Read the above test description to understand what this test should do
-
-
       // Array with questions to be used in the test and passed to the Quiz constructor
       const questions = [
         {
@@ -381,78 +341,41 @@ describe("Quiz", () => {
         },
       ];
 
-      // YOUR CODE HERE:
-      //
-      // 2. Instantiate a new Quiz object with the test questions
-
-      // 3. Call the `filterQuestionsByDifficulty()` method with a string as a 1st argument (wrong data type).
+      // Instantiate a new Quiz object with the test questions
+      const quiz = new Quiz(questions, "test", 60);
 
-      // 4. Check if the questions array is still the same as the original (it hasn't been filtered)
+      // Call the `filterQuestionsByDifficulty()` method with a string as a 1st argument (wrong data type).
+      quiz.filterQuestionsByDifficulty("foo");
 
+      // Check if the questions array is still the same as the original (it hasn't been filtered)
+      expect(quiz.questions).toEqual(questions);
     });
   });
 
 
-  // ****************************************************************************************************
-  // DAY 2
-  //
-  // The 1st test is already written for you -  checking if the 'reduce()' array method is used.
-  //
-  // The test block below is currently skipped ('xdescribe').
-  // Once you start working on the tests, change the 'xdescribe' to 'describe' to enable the tests.
-  // ****************************************************************************************************
-
-  xdescribe("averageDifficulty() method", () => {
-    it("should use the 'reduce()' array method on the 'questions' array", () => {
+  describe("averageDifficulty() method", () => {
+    it("should be defined", () => {
       // Instantiate a new Quiz object
       const quiz = new Quiz([], "test", 60);
-      // Set up a spy on the 'reduce()' array method to track calls to it
-      const reduceSpy = spyOn(quiz.questions, "reduce");
-
-      // Call the 'averageDifficulty()' method
-      quiz.averageDifficulty();
-
-      // Check if the 'reduce()' array method was called on the 'questions' array
-      expect(reduceSpy).toHaveBeenCalled();
-      // Check that the 'reduce()' array method was called only once
-      expect(reduceSpy).toHaveBeenCalledTimes(1);
-      // Check that the 'reduce()' array method was called correctly, with a function as its 1st argument and optional 2nd argument
-      expect(reduceSpy.calls.allArgs()[0][0]).toEqual(jasmine.any(Function));
-    });
-
-
-    // ****************************************************************************************************
-    // DAY 2: 'averageDifficulty()' method
-    //      
-    // Below are 4 tests that you need to write for the 'averageDifficulty()' method.
-    // ****************************************************************************************************
-      
-
-    it("should be defined", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
-
-      // 2. Check if the averageDifficulty() method is defined
+      // Check if the averageDifficulty() method is defined
+      expect(quiz.averageDifficulty).toBeDefined();
 
     });
 
     it("should be a function", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
-
-      // 2. Check if the .averageDifficulty is a function
+      // Instantiate a new Quiz object
+      const quiz = new Quiz([], "test", 60);
 
+      // Check if the .averageDifficulty is a function
+      expect(typeof quiz.averageDifficulty).toBe("function");
     });
 
     it("should receive no arguments", () => {
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object
-
-      // 2. Check that the averageDifficulty() method takes no arguments
+      // Instantiate a new Quiz object
+      const quiz = new Quiz([], "test", 60);
 
+      // Check that the averageDifficulty() method takes no arguments
+      expect(quiz.averageDifficulty.length).toEqual(0);
     });
 
     it("should return the average difficulty of the questions in the quiz", () => {
@@ -490,14 +413,13 @@ describe("Quiz", () => {
         },
       ];
 
-      // YOUR CODE HERE:
-      //
-      // 1. Instantiate a new Quiz object with the test questions
-
-      // 2. Check that the averageDifficulty() method returns the correct average when called
+      // Instantiate a new Quiz object with the test questions
+      const quiz = new Quiz(questions, "test", 60);
 
+      // Check that the averageDifficulty() method returns the correct average when called
+      expect(quiz.averageDifficulty()).toEqual(1.8);
     });
-  });
+  }); 
 });