fix: add input validation and tests

smart_contract/contracts/Transactions.sol

@@ -1,12 +1,13 @@
 // SPDX-License-Identifier: UNLICENSED
 
 pragma solidity ^0.8.0;
-
-import "hardhat/console.sol";
+ 
+// import "hardhat/console.sol";
 
 contract Transactions {
     uint256 transactionCount;
 
+
     event Transfer(address from, address receiver, uint amount, string message, uint256 timestamp, string keyword);
 
     struct TransferStruct {
@@ -19,8 +20,16 @@ contract Transactions {
     }
 
     TransferStruct[] transactions;
-
+
+/// @notice Adds a transaction to the blockchain.
+/// @param receiver The address receiving funds.
+/// @param amount The amount being sent.
+/// @param message A message associated with the transaction.
+/// @param keyword A keyword for categorizing the transaction.
     function addToBlockchain(address payable receiver, uint amount, string memory message, string memory keyword) public {
+        require(receiver != address(0), "Invalid receiver address");
+        require(amount > 0, "Amount must be greater than 0");
+
         transactionCount += 1;
         transactions.push(TransferStruct(msg.sender, receiver, amount, message, block.timestamp, keyword));
 

smart_contract/test/sample-test.js

@@ -1,19 +1,38 @@
 const { expect } = require("chai");
 const { ethers } = require("hardhat");
 
-describe("Greeter", function () {
-  it("Should return the new greeting once it's changed", async function () {
-    const Greeter = await ethers.getContractFactory("Greeter");
-    const greeter = await Greeter.deploy("Hello, world!");
-    await greeter.deployed();
-
-    expect(await greeter.greet()).to.equal("Hello, world!");
-
-    const setGreetingTx = await greeter.setGreeting("Hola, mundo!");
-
-    // wait until the transaction is mined
-    await setGreetingTx.wait();
-
-    expect(await greeter.greet()).to.equal("Hola, mundo!");
+describe("Transactions", function () {
+  let transactions
+  beforeEach( async()=>{
+    const Transactions = await ethers.getContractFactory("Transactions");
+    transactions = await Transactions.deploy();
+  })
+  it("Should reject zero address", async function () {
+
+    // await transactions.deployed();
+    const zeroAddress = ethers.ZeroAddress
+    // await expect(transactions.addToBlockchain(zeroAddress, 300,"message", "keyword")).to.be.revertedWithCustomError(transactions,"Transactions__InvalidReceiver")
+      // Note: Changed the error checking syntax
+      await expect(
+        transactions.addToBlockchain(
+          ethers.constants.AddressZero, // Invalid address
+          100, "Hello", "Test"
+        )
+      ).to.be.revertedWith("Invalid receiver address");
+  });
+  it("Should reject zero amount", async function () {
+    const Transactions = await ethers.getContractFactory("Transactions");
+     transactions = await Transactions.deploy();
+    // await transactions.deployed();
+    const zeroAddress = ethers.ZeroAddress
+    // await expect(transactions.addToBlockchain(zeroAddress, 300,"message", "keyword")).to.be.revertedWithCustomError(transactions,"Transactions__InvalidReceiver")
+      // Note: Changed the error checking syntax
+      const address = "0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266"
+      await expect(
+        transactions.addToBlockchain(
+          address, 
+          0, "Hello", "Test"
+        )
+      ).to.be.revertedWith("Amount must be greater than 0");
   });
 });