test/jdk/java/math/BigDecimal/IntValueExactTests.java

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/**
 * @test
 * @bug 8211936
 * @summary Tests of BigDecimal.intValueExact
 */
import java.math.*;
import java.util.List;
import java.util.Map;
import static java.util.Map.entry;

public class IntValueExactTests {
    public static void main(String... args) {
        int failures = 0;

        failures += intValueExactSuccessful();
        failures += intValueExactExceptional();

        if (failures > 0) {
            throw new RuntimeException("Incurred " + failures +
                                       " failures while testing intValueExact.");
        }
    }

    private static int simpleIntValueExact(BigDecimal bd) {
        return bd.toBigIntegerExact().intValue();
    }

    private static int intValueExactSuccessful() {
        int failures = 0;

        // Strings used to create BigDecimal instances on which invoking
        // intValueExact() will succeed.
        Map<BigDecimal, Integer> successCases =
            Map.ofEntries(entry(new BigDecimal("2147483647"),    Integer.MAX_VALUE), // 2^31 -1
                          entry(new BigDecimal("2147483647.0"),  Integer.MAX_VALUE),
                          entry(new BigDecimal("2147483647.00"), Integer.MAX_VALUE),

                          entry(new BigDecimal("-2147483648"),   Integer.MIN_VALUE), // -2^31
                          entry(new BigDecimal("-2147483648.0"), Integer.MIN_VALUE),
                          entry(new BigDecimal("-2147483648.00"),Integer.MIN_VALUE),

                          entry(new BigDecimal("1e0"),    1),
                          entry(new BigDecimal(BigInteger.ONE, -9),   1_000_000_000),

                          entry(new BigDecimal("0e13"),   0), // Fast path zero
                          entry(new BigDecimal("0e32"),   0),
                          entry(new BigDecimal("0e512"), 0),

                          entry(new BigDecimal("10.000000000000000000000000000000000"), 10));

        for (var testCase : successCases.entrySet()) {
            BigDecimal bd = testCase.getKey();
            int expected = testCase.getValue();
            try {
                int intValueExact = bd.intValueExact();
                if (expected != intValueExact ||
                    intValueExact != simpleIntValueExact(bd)) {
                    failures++;
                    System.err.println("Unexpected intValueExact result " + intValueExact +
                                       " on " + bd);
                }
            } catch (Exception e) {
                failures++;
                System.err.println("Error on " + bd + "\tException message:" + e.getMessage());
            }
        }
        return failures;
    }

    private static int intValueExactExceptional() {
        int failures = 0;
        List<BigDecimal> exceptionalCases =
            List.of(new BigDecimal("2147483648"), // Integer.MAX_VALUE + 1
                    new BigDecimal("2147483648.0"),
                    new BigDecimal("2147483648.00"),
                    new BigDecimal("-2147483649"), // Integer.MIN_VALUE - 1
                    new BigDecimal("-2147483649.1"),
                    new BigDecimal("-2147483649.01"),

                    new BigDecimal("9999999999999999999999999999999"),
                    new BigDecimal("10000000000000000000000000000000"),

                    new BigDecimal("0.99"),
                    new BigDecimal("0.999999999999999999999"));

        for (BigDecimal bd : exceptionalCases) {
            try {
                int intValueExact = bd.intValueExact();
                failures++;
                System.err.println("Unexpected non-exceptional intValueExact on " + bd);
            } catch (ArithmeticException e) {
                // Success;
            }
        }
        return failures;
    }
}