TestConstructor.cpp

#include "BigInteger.h"
#include "BigIntegerException.h"
#include "gtest\gtest.h"

/**
*   To test BigInteger constructors using toString function
*   9 cases:
*       1. default constructor
*       2. constructor with a VALID short string argument
*       3. constructor with a VALID long string argument
*       (within long long range)
*       4. constructor with a VALID long string argument
*       (out of long long range)
*       5. constructor with an INVALID short string - exception
*       6. constructor with an INVALID long string - exception
*       7. constructor with an empty string - exception
*       8. constructor with leading 0
*       9. copy constructor
*/

/**
*   Case 1
*/
TEST(TestConstructor, defaultConstructor) {
    BigInteger bigInt1;
    EXPECT_EQ("0", bigInt1.toString());
}

/**
*   Case 2, 3, 4
*/
TEST(TestConstructor, constructorWithValidString) {
    // case 2
    BigInteger bigInt1("123");
    EXPECT_EQ("123", bigInt1.toString());

    // case 3
    BigInteger bigInt2("1234567890123456789");
    EXPECT_EQ("1234567890123456789", bigInt2.toString());

    // case 4
    BigInteger bigInt3("123456789012345678901");
    EXPECT_EQ("123456789012345678901", bigInt3.toString());
}

/**
*   Case 5, 6, 7:
*   (a): derived class
*   (b): base class
*
* Notes:
*   Because BigIntegerException is base class of NumberFormatException,
*   same error should be able to catch by base class
*/
TEST(TestConstructor, constructorWithInvalidString) {
    // case 5a
    EXPECT_THROW(BigInteger bigInt5("123a"), NumberFormatException);

    // case 5b
    EXPECT_THROW(BigInteger bigInt5("123a"), BigIntegerException);

    // case 6a
    EXPECT_THROW(
        BigInteger bigInt5("123456789012345678901234567890a"),
        NumberFormatException);

    // case 6b
    EXPECT_THROW(
        BigInteger bigInt5("123456789012345678901234567890a"),
        BigIntegerException);

    // case 7
    EXPECT_THROW(
        BigInteger bigInt5(""),
        BigIntegerException);
}

/**
*   Case 8
*/
TEST(TestConstructor, constructorWithLeadingZero) {
    BigInteger bigInt("000");
    EXPECT_EQ("0", bigInt.toString());

    bigInt = BigInteger("0001");
    EXPECT_EQ("1", bigInt.toString());
}

/**
*   Case 9
*/
TEST(TestConstructor, copyConstructor) {
    BigInteger bigInt1("123");

    BigInteger bigInt2(bigInt1);
    EXPECT_EQ("123", bigInt2.toString());

    bigInt1 = BigInteger("456");
    EXPECT_EQ("123", bigInt2.toString());
}