TDD: implement repeatStr with tests

Author: salahalsabhi

practice-tdd/repeat-str.js

@@ -1,5 +1,10 @@
-export function repeatStr() {
-  // Your implementation of this function must *not* call String.prototype.repeat (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/repeat).
-  // The goal is to re-implement that function, not to use it.
-  return "hellohellohello";
+export function repeatStr(string, count) {
+  let result = "";
+  if (count < 0) {
+    throw new Error("wrong input");
+  }
+  for (let n = 0; n < count; n++) {
+    result = result + string;
+  }
+  return result;
 }

practice-tdd/repeat-str.test.js

@@ -20,13 +20,30 @@ test("should repeat the string count times", () => {
 // Given a target string `str` and a `count` equal to 1,
 // When the repeatStr function is called with these inputs,
 // Then it should return the original `str` without repetition.
+test("should repeat the string one time", () => {
+  const str = "javascript";
+  const count = 1;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("javascript");
+});
+
 
 // Case: Handle count of 0:
 // Given a target string `str` and a `count` equal to 0,
 // When the repeatStr function is called with these inputs,
 // Then it should return an empty string.
+test("should repeat the string 0 times", () => {
+  const str = "Hi there";
+  const count = 0;
+  const repeatedStr = repeatStr(str, count);
+  expect(repeatedStr).toEqual("");
+});
+
 
 // Case: Handle negative count:
 // Given a target string `str` and a negative integer `count`,
 // When the repeatStr function is called with these inputs,
 // Then it should throw an error, as negative counts are not valid.
+test("should throw an error with negative count times", () => {
+  expect(() => repeatStr("hello", -5)).toThrow("wrong input");
+});