Add tests for snake case algorithm

String/CheckSnakeCase.js

@@ -3,18 +3,18 @@
 // Problem Source & Explanation: https://en.wikipedia.org/wiki/Naming_convention_(programming)
 
 /**
- * CheckSnakeCase method returns true if the string in snake_case, else return the false.
+ * checkSnakeCase method returns true if the string in snake_case, else return the false.
  * @param {String} varName the name of the variable to check.
  * @returns `Boolean` return true if the string is in snake_case, else return false.
  */
-const CheckSnakeCase = (varName) => {
+const checkSnakeCase = (varName) => {
   // firstly, check that input is a string or not.
   if (typeof varName !== 'string') {
-    return new TypeError('Argument is not a string.')
+    throw new TypeError('Argument is not a string.')
   }
 
   const pat = /(.*?)_([a-zA-Z])*/
   return pat.test(varName)
 }
 
-module.exports = CheckSnakeCase
+export { checkSnakeCase }

String/test/CheckSnakeCase.test.js

@@ -0,0 +1,18 @@
+import { checkSnakeCase } from '../CheckSnakeCase'
+describe('checkSnakeCase', () => {
+  it('expect to throw an error if input is not a string', () => {
+    expect(() => checkSnakeCase(0)).toThrow()
+  })
+
+  it('expects to return true if the input is in snake case format', () => {
+    const value = 'docker_build'
+    const result = checkSnakeCase(value)
+    expect(result).toBe(true)
+  })
+
+  it('expects to return false if the input is not in snake case format', () => {
+    const value = 'dockerBuild'
+    const result = checkSnakeCase(value)
+    expect(result).toBe(false)
+  })
+})