test(the-typeinator): add index.test.js for prototypes-to-classes

- Add comprehensive test suite for Robot and Humanoid classes
- Implement conditional test skipping for educational workflow
- Tests skip when index.js is empty (learner mode)
- Tests run with TEST_SOLUTIONS=true (validation mode)
- Cover class construction, inheritance, and method functionality
- Include console.log mocking for announce/charge/move methods
- Validate power management and error handling logic

Author: Felsilva15

projects/from-javascript-to-typescript/the-typeinator/02-prototypes-to-classes/index.js

@@ -1,5 +1,2 @@
 // Put your Robot and Humanoid classes here! ✨
 // See ./original.js for their older JavaScript code.
-
-module.exports.Humanoid = Humanoid;
-module.exports.Robot = Robot;

projects/from-javascript-to-typescript/the-typeinator/02-prototypes-to-classes/index.test.js

@@ -0,0 +1,162 @@
+const index = require("./index");
+const solution = require("./solution");
+
+// Use solution when TEST_SOLUTIONS is true, otherwise try to use index (may be empty)
+const { Robot, Humanoid } = process.env.TEST_SOLUTIONS ? solution : index || {};
+
+describe("02 - Prototypes to Classes", () => {
+	// Skip tests if Robot/Humanoid classes are not implemented
+	const shouldSkip = !Robot || !Humanoid;
+
+	describe("Robot", () => {
+		(shouldSkip ? test.skip : test)(
+			"creates a robot with name, abilities, and power",
+			() => {
+				const robot = new Robot("R2-D2", ["beep", "navigate"]);
+
+				expect(robot.name).toBe("R2-D2");
+				expect(robot.abilities).toEqual(["beep", "navigate"]);
+				expect(robot.power).toBe(100);
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"announce method logs greetings and abilities",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const robot = new Robot("C-3PO", ["translate", "worry"]);
+
+				robot.announce();
+
+				expect(consoleSpy).toHaveBeenCalledWith("Greetings. I am C-3PO.");
+				expect(consoleSpy).toHaveBeenCalledWith("I am able to translate.");
+				expect(consoleSpy).toHaveBeenCalledWith("I am able to worry.");
+
+				consoleSpy.mockRestore();
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"charge method increases power and logs status",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const robot = new Robot("Wall-E", ["clean"]);
+				robot.power = 50;
+
+				robot.charge(30);
+
+				expect(robot.power).toBe(80);
+				expect(consoleSpy).toHaveBeenCalledWith(
+					"Recharged power supplies to 80.",
+				);
+
+				consoleSpy.mockRestore();
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"charge method caps power at 100 and logs optimal capacity",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const robot = new Robot("BB-8", ["roll"]);
+				robot.power = 90;
+
+				robot.charge(20);
+
+				expect(robot.power).toBe(100);
+				expect(consoleSpy).toHaveBeenCalledWith(
+					"Recharged power supplies to 100.",
+				);
+				expect(consoleSpy).toHaveBeenCalledWith(
+					"I am at optimal operational capacity.",
+				);
+
+				consoleSpy.mockRestore();
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"move method reduces power and logs movement",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const robot = new Robot("EVE", ["scan"]);
+
+				robot.move(25);
+
+				expect(robot.power).toBe(75);
+				expect(consoleSpy).toHaveBeenCalledWith("Moving 25 units.");
+
+				consoleSpy.mockRestore();
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"move method prevents movement when insufficient power",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const robot = new Robot("WALL-E", ["compact"]);
+				robot.power = 10;
+
+				robot.move(25);
+
+				expect(robot.power).toBe(10);
+				expect(consoleSpy).toHaveBeenCalledWith(
+					"I do not have enough power to move 25 units.",
+				);
+
+				consoleSpy.mockRestore();
+			},
+		);
+	});
+
+	describe("Humanoid", () => {
+		(shouldSkip ? test.skip : test)(
+			"creates a humanoid with name, abilities, power, and catchphrase",
+			() => {
+				const humanoid = new Humanoid(
+					"Data",
+					["compute", "analyze"],
+					"Fascinating",
+				);
+
+				expect(humanoid.name).toBe("Data");
+				expect(humanoid.abilities).toEqual(["compute", "analyze"]);
+				expect(humanoid.power).toBe(100);
+				expect(humanoid.catchphrase).toBe("Fascinating");
+			},
+		);
+
+		(shouldSkip ? test.skip : test)(
+			"announce method logs greetings, abilities, and catchphrase",
+			() => {
+				const consoleSpy = jest.spyOn(console, "log").mockImplementation();
+				const humanoid = new Humanoid(
+					"T-800",
+					["terminate", "protect"],
+					"I'll be back",
+				);
+
+				humanoid.announce();
+
+				expect(consoleSpy).toHaveBeenCalledWith("Greetings. I am T-800.");
+				expect(consoleSpy).toHaveBeenCalledWith("I am able to terminate.");
+				expect(consoleSpy).toHaveBeenCalledWith("I am able to protect.");
+				expect(consoleSpy).toHaveBeenCalledWith(" > I'll be back <");
+
+				consoleSpy.mockRestore();
+			},
+		);
+
+		(shouldSkip ? test.skip : test)("inherits Robot methods correctly", () => {
+			const humanoid = new Humanoid(
+				"Vision",
+				["phase", "fly"],
+				"I am inevitable",
+			);
+
+			expect(typeof humanoid.charge).toBe("function");
+			expect(typeof humanoid.move).toBe("function");
+			expect(humanoid instanceof Robot).toBe(true);
+		});
+	});
+});