Fix/convert inches to centimeters (#529)

* Changes tests in order to be useful

* Fix convertInchesToCentimeters

* Adds convertCentimetersToInches issue

lib/convertCentimetersToInches.js

@@ -0,0 +1,11 @@
+/**
+ * Convert centimeters to inches where 1 cm equals 0.393701 inches
+ * @param {number} cm
+ * @return returned value in inches
+ */
+function convertCentimetersToInches(cm){
+  // Your code goes here
+  throw("Invalid Type");
+}
+
+module.exports = convertCentimetersToInches;

lib/convertInchesToCentimeters.js

@@ -1,11 +1,14 @@
 /**
-* Convert inches to centimeters
+* Convert inches to centimeters where 1 inch equals 2.54 cm
 * @param {number} inches
 * @return returned value in centimeters
 */
 function convertInchesToCentimeters(inches){
-  //Code goes here
-  throw new Error("Invalid Argument");
+  if (typeof inches === "number" && inches === inches === isFinite(inches)) {
+    return inches * 2.54;
+  } else {
+    throw("Invalid Type");
+  }
 }
 
 module.exports = convertInchesToCentimeters;

test/convertCentimetersToInches.test.js

@@ -0,0 +1,18 @@
+const { convertCentimetersToInches } = require("../lib");
+
+describe("convertCentimetersToInches", () => {
+  test("12 cm is 4.72 inches", () => {
+    expect(convertCentimetersToInches(12)).toBe(4.72);
+  });
+
+  test("30 cm is 11.81 inches", () => {
+    expect(convertCentimetersToInches(30)).toBe(11.81);
+  });
+
+  test("Throw error on invalid type", () => {
+    expect(() => convertCentimetersToInches("a cm")).toThrow("Invalid Type");
+    expect(() => convertCentimetersToInches(null)).toThrow("Invalid Type");
+    expect(() => convertCentimetersToInches(undefined)).toThrow("Invalid Type");
+    expect(() => convertCentimetersToInches({})).toThrow("Invalid Type");
+  });
+});

test/convertInchesToCentimeters.test.js

@@ -1,15 +1,22 @@
 const { convertInchesToCentimeters } = require("../lib");
 
 describe("convertInchesToCentimeters", () => {
-  it("Should return converted inches to centimeters", () => {
-    expect(() => convertInchesToCentimeters(5).toBe(12.7000254000508));
-    expect(() => convertInchesToCentimeters(7).toBe(17.78003556007112));
-    // add more cases
+  test("5 inches is 12.70 cm", () => {
+    expect(convertInchesToCentimeters(5)).toBe(12.7);
   });
 
-  it("Should check if parameter is valid", () => {
-    expect(() => convertInchesToCentimeters({})).toThrow("Invalid Argument");
-    expect(() => convertInchesToCentimeters([1,2])).toThrow("Invalid Argument");
-    // add more cases
+  test("7 inches is 17.78 cm", () => {
+    expect(convertInchesToCentimeters(7)).toBe(17.78);
+  });
+
+  test("12 inches is 30.48 cm", () => {
+    expect(convertInchesToCentimeters(12)).toBe(30.48);
+  });
+
+  test("Throw error on invalid type", () => {
+    expect(() => convertInchesToCentimeters("a inch")).toThrow("Invalid Type");
+    expect(() => convertInchesToCentimeters(null)).toThrow("Invalid Type");
+    expect(() => convertInchesToCentimeters(undefined)).toThrow("Invalid Type");
+    expect(() => convertInchesToCentimeters({})).toThrow("Invalid Type");
   });
 });