is-valid-triangle.test.js

// Implement a function isValidTriangle

const { default: expect } = require("expect");

// 🗝️ Terms
// the Triangle Inequality says: the sum of any two sides is always greater than the third side.
// practical examples:
// Side a = 3
// Side b = 3
// Side c = 3

// This is a valid triangle, because a plus b = 6 and 6 is greater than 3
// Another way to write this is a + b > c
// It's also true that b + c > a
// It's also true that a + c > b

// In our function isValidTriangle, we need to return false for any triangle where the sum of any two sides is less than or equal to the length of the third side.
// and we need to return true for any triangle where the sum of any two sides is greater than the length of the third side.

// Acceptance criteria:

// Given the lengths of three sides of a triangle (a, b, c),
// When the function isValidTriangle is called with these side lengths as input,
// Then it should:

// scenario: invalid triangle
// Given the side lengths a, b, and c,
// When the sum of any two side lengths is less than or equal to the length of the third side (i.e., a + b <= c, a + c <= b, b + c <= a),
// Then it should return false because these conditions violate the Triangle Inequality, which states that the sum of the lengths of any two sides of a triangle must be greater than the length of the third side.

// scenario: invalid triangle
// Check for Valid Input:
// Given the sides a, b, and c,
// When any of the sides are less than or equal to zero,
// Then it should return false because a triangle cannot have zero or negative side lengths.

// scenario: valid triangle
// Given valid side lengths where the sum of any two sides is greater than the third side,
// When the function is called with these values as input,
// Then it should return true because the input forms a valid triangle.

// This specification outlines the behavior of the isValidTriangle function for different input scenarios, ensuring it properly checks for invalid side lengths and whether they form a valid triangle according to the Triangle Inequality Theorem.

function isValidTriangle(a,b,c){
    if (a+b<=c || a+c<=b || b+c<=a){
        return false;
    }
    else if (a<=0 || b<=0 || c<=0){
        return false;
    }
    else if(a+b>c && a+c>b && b+c>a){
    return true;
    }
}

test("Check if the triangle is valid or not", function () {
    
    expect(isValidTriangle(3, 3, 3)).toBe(true);
    expect(isValidTriangle(3, -3, 3)).toBe(false);
    expect(isValidTriangle(1, 2, 5)).toBe(false);
});