import junit.framework.TestCase;

import java.math.BigInteger;

public class CheckPrimeNumberTest extends TestCase {

    public void testPrimeNumbersUpTo1000() {
        // "List of Prime Numbers up to 1000"
        // https://www.miniwebtool.com/list-of-prime-numbers/?to=1000
        final int[] primeNumbers = {
                2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97,
                101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199,
                211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293,
                307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397,
                401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499,
                503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599,
                601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691,
                701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797,
                809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887,
                907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997,
                9999
        };
        StringBuilder errorMessage = new StringBuilder();

        int arrIdx = 0;
        for (int testNumber = 0; testNumber <= 1000; ++testNumber) {
            final boolean isPrime = (testNumber == primeNumbers[arrIdx]);

            final BigInteger inputValueToTest = new BigInteger(String.valueOf(testNumber));

            final boolean computedPrimeFlag = CheckPrimeNumber.isPrime(inputValueToTest);

            if (computedPrimeFlag != isPrime) {
                errorMessage.append("  isPrime(").append(inputValueToTest).append(")")
                        .append(" returned ").append(computedPrimeFlag).append(",")
                        .append(" but the correct value is ").append(isPrime)
                        .append(System.lineSeparator());
            }

            if (isPrime) {
                ++arrIdx;
            }
        }

        if (errorMessage.length() > 0) {
            fail("ERROR:" + System.lineSeparator() + errorMessage.toString());
        }
    }

}