style: cleanup PascalTriangle (TheAlgorithms#1606)

* tests: add missing tests for `PascalTriangle`

* style: remove redundant branch in `generate`

* tests: simplify tests of `PascalTriangle`

Author: vil02

Maths/PascalTriangle.js

@@ -17,8 +17,6 @@ const generate = (numRows) => {
     return []
   } else if (numRows === 1) {
     return [[1]]
-  } else if (numRows === 2) {
-    return [[1], [1, 1]]
   } else {
     for (let i = 2; i < numRows; i++) {
       addRow(triangle)

Maths/test/PascalTriangle.test.js

@@ -1,20 +1,20 @@
+import { expect } from 'vitest'
 import { generate } from '../PascalTriangle'
 
 describe('Pascals Triangle', () => {
-  it('should have the the same length as the number', () => {
-    const pascalsTriangle = generate(5)
-    expect(pascalsTriangle.length).toEqual(5)
-  })
-  it('should have same length as its index in the array', () => {
-    const pascalsTriangle = generate(5)
+  it.each([
+    [0, []],
+    [1, [[1]]],
+    [2, [[1], [1, 1]]],
+    [3, [[1], [1, 1], [1, 2, 1]]],
+    [4, [[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]]],
+    [5, [[1], [1, 1], [1, 2, 1], [1, 3, 3, 1]], [1, 4, 6, 4, 1]]
+  ])('check with %j', (input, expected) => {
+    const pascalsTriangle = generate(input)
+    expect(pascalsTriangle.length).toEqual(input)
     pascalsTriangle.forEach((arr, index) => {
       expect(arr.length).toEqual(index + 1)
     })
-  })
-  it('should return an array of arrays', () => {
-    const pascalsTriangle = generate(3)
-    expect(pascalsTriangle).toEqual(
-      expect.arrayContaining([[1], [1, 1], [1, 2, 1]])
-    )
+    expect(pascalsTriangle).toEqual(expect.arrayContaining(expected))
   })
 })