Add tests to Math (#423)

* Add prettier config

* test: add test to check for absolute function

* chore: es5 to es6

* test: add test to check mean function

* test: add test for sum of digit

* test: add test for factorial

* test: add test for fibonnaci

* test: add test for find HCF

* test: add test for lcm

* test: add gridget test

* test: add test for mean square error

* test: add test for modular binary exponentiation

* test: add tests for palindrome

* test: add test for pascals triangle

* test: add tests for polynomial

* test: add tests for prime check

* test: add tests for reverse polish notation

* test: add tests for sieve of eratosthenes

* test: add tests for pi estimation monte carlo method

* chore: move tests to test folder

* chore: fix standardjs errors

String/test/PatternMatching.test.js

@@ -0,0 +1,28 @@
+import { checkIfPatternExists } from '../PatternMatching'
+describe('checkIfPatternExists', () => {
+  it('expects to find a pattern with correct input', () => {
+    const text = 'AABAACAADAABAAAABAA'
+    const pattern = 'AABA'
+    const SUT = checkIfPatternExists(text.toLowerCase(), pattern.toLowerCase())
+    expect(SUT).toBe('Given pattern is found at index 0')
+  })
+  it('expects to return a message when there is no pattern', () => {
+    const text = 'ABCDEFG'
+    const pattern = 'AEG'
+    const SUT = checkIfPatternExists(text.toLowerCase(), pattern.toLowerCase())
+    expect(SUT).toBe(undefined)
+  })
+  it('expects to find a pattern independent of casing', () => {
+    const text = 'AbCAAAAAAB'
+    const pattern = 'abc'
+    const SUT = checkIfPatternExists(text, pattern)
+    expect(SUT).toBe(undefined)
+  })
+  it('expects to throw an error message when given inpuut is not a string', () => {
+    const text = 123444456
+    const pattern = 123
+    expect(() => checkIfPatternExists(text, pattern)).toThrow(
+      'Given input is not a string'
+    )
+  })
+})