test/jdk/java/math/BigDecimal/ValueOfDouble.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 *
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 * 2 along with this work; if not, write to the Free Software Foundation,
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/*
 * @test
 * @bug 8356709
 * @summary Test Double.toString(double)
 * @run junit ValueOfDouble
 */


import org.junit.jupiter.api.Test;

import java.math.BigDecimal;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;


public class ValueOfDouble {
    private static final String DIGITS = "1234567000003456789"; // Enough digits to fill a long

    @Test
    public void testValueOfDouble() {
        checkValue(0.0);
        checkValue(-0.0);
        checkValue(Math.PI);
        checkValue(-Math.PI);
        checkValue(Double.MAX_VALUE);
        checkValue(Double.MIN_VALUE);
        checkValue(1e-44); // Lots of digits with lots of 9s

        for (int prec = 1; prec < DIGITS.length(); prec++) {
            String prefix = DIGITS.substring(0, prec);
            for (int exp = -30; exp < 30; exp++) {
                double value = Double.parseDouble(prefix + "e" + exp);
                checkValue(value);
                checkValue(-value);
            }
        }
    }

    private static void checkValue(double value) {
        BigDecimal expected = new BigDecimal(Double.toString(value));
        assertEquals(expected, BigDecimal.valueOf(value));
    }

    @Test
    public void testExceptions() {
        assertThrows(NumberFormatException.class, () -> BigDecimal.valueOf(Double.NaN));
        assertThrows(NumberFormatException.class, () -> BigDecimal.valueOf(Double.POSITIVE_INFINITY));
        assertThrows(NumberFormatException.class, () -> BigDecimal.valueOf(Double.NEGATIVE_INFINITY));
    }
}