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contracts...Library_Test.sol

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.0;

import "remix_tests.sol"; // this import is automatically injected by Remix.
import "./Library.sol";

contract LibraryTest is Library {
    // Run all test functions in sequence, after initializing library as following.
    function TestInitLibrary() public {
        uint firstBook = 9781234567890;
        for(uint i = 0; i < 10; i++) {
            addBook(firstBook + i, 2);
        }
    }
    
    // Run this from a first sender.
    function TestScenario1() public {
        uint[] memory books = viewBooks();
        Assert.equal(books[5], uint(9781234567895), "Fifth book should be 9781234567895.");
        Assert.equal(books.length, uint(10), "There should be 10 available books.");
        borrowBook(9781234567895);
        books = viewBooks();
        Assert.equal(books[5], uint(9781234567896), "Fifth available book should now be 9781234567896, as we already got 9781234567895.");
        Assert.equal(books.length, uint(9), "There should now be 9 available books left to borrow.");
        borrowBook(9781234567899);
        returnBook(9781234567899);
        Assert.equal(books[8], uint(9781234567899), "Last available book should now be 9781234567899, as borrowed and returned it.");
        Assert.equal(books.length, uint(9), "There should still be 9 available books left to borrow.");
    }
    
    // Run this from a second sender. Test independent interaction with more users.
    function TestScenario2() public {
        uint[] memory books = viewBooks();
        Assert.equal(books[5], uint(9781234567895), "Fifth book should be 9781234567895.");
        Assert.equal(books.length, uint(10), "There should be 10 available books.");
        borrowBook(9781234567895);
        books = viewBooks();
        Assert.equal(books[5], uint(9781234567896), "Fifth available book should now be 9781234567896, as we already got 9781234567895.");
        Assert.equal(books.length, uint(9), "There should now be 9 available books left to borrow.");
    }
    
    // Run this from a third sender. Test depletion of a book by previous users.
    function TestScenario3() public {
        uint[] memory books = viewBooks();
        Assert.equal(books[5], uint(9781234567896), "Fifth book should be 9781234567896, as the previous 2 senders depleted 9781234567895.");
        Assert.equal(books.length, uint(9), "There should be 9 available books.");
        borrowBook(9781234567899);
    }
    
    function TestHistory() public {
        Assert.equal(borrowHistory(9781234567895).length, uint(2), "9781234567895 should have been borrowed by a total of 2 users");
        Assert.equal(borrowHistory(9781234567899).length, uint(2), "9781234567899 should have been borrowed by a total of 2 users");
    }
    
    // TODO Find way to test failing transactions.
}