* test/bigdecimal/test_bigdecimal.rb: add tests to achieve over 90%

  test coverage of bigdecimal.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@19401 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 681 insertions, 0 deletions

diff --git a/test/bigdecimal/test_bigdecimal.rb b/test/bigdecimal/test_bigdecimal.rb
new file mode 100644
index 0000000000..c3899033e3
--- /dev/null
+++ b/test/bigdecimal/test_bigdecimal.rb
@@ -0,0 +1,681 @@
+require "test/unit"
+require "bigdecimal"
+
+class TestBigDecimal < Test::Unit::TestCase
+  def setup
+    BigDecimal.mode(BigDecimal::EXCEPTION_ALL, true)
+    BigDecimal.mode(BigDecimal::EXCEPTION_UNDERFLOW, true)
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true)
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_HALF_UP)
+    BigDecimal.limit(0)
+  end
+
+  def test_version
+    assert_equal("1.0.1", BigDecimal.ver)
+  end
+
+  def test_global_new
+    assert_equal(1, BigDecimal("1"))
+    assert_equal(1, BigDecimal("1", 1))
+    assert_raise(ArgumentError) { BigDecimal("1", -1) }
+  end
+
+  def test_new
+    assert_equal(1, BigDecimal.new("1"))
+    assert_equal(1, BigDecimal.new("1", 1))
+    assert_equal(1, BigDecimal.new(" 1 "))
+    assert_equal(111, BigDecimal.new("1_1_1_"))
+    assert_equal(0, BigDecimal.new("_1_1_1"))
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    assert_equal( 1, BigDecimal.new("Infinity").infinite?)
+    assert_equal(-1, BigDecimal.new("-Infinity").infinite?)
+    assert_equal(true, BigDecimal.new("NaN").nan?)
+  end
+
+  def _test_mode(type)
+    BigDecimal.mode(type, true)
+    assert_raise(FloatDomainError) { yield }
+
+    BigDecimal.mode(type, false)
+    assert_nothing_raised { yield }
+  end
+
+  def test_mode
+    assert_raise(TypeError) { BigDecimal.mode(BigDecimal::EXCEPTION_ALL, 1) }
+    assert_raise(TypeError) { BigDecimal.mode(BigDecimal::ROUND_MODE, 256) }
+    assert_raise(TypeError) { BigDecimal.mode(0xf000, true) }
+  end
+
+  def test_exception_nan
+    _test_mode(BigDecimal::EXCEPTION_NaN) { BigDecimal.new("NaN") }
+  end
+
+  def test_exception_infinity
+    _test_mode(BigDecimal::EXCEPTION_INFINITY) { BigDecimal.new("Infinity") }
+  end
+
+  def test_exception_underflow
+    _test_mode(BigDecimal::EXCEPTION_UNDERFLOW) do
+      x = BigDecimal.new("0.1")
+      100.times do
+        x *= x
+        break if x == false
+      end
+    end
+  end
+
+  def test_exception_overflow
+    _test_mode(BigDecimal::EXCEPTION_OVERFLOW) do
+      x = BigDecimal.new("10")
+      100.times do
+        x *= x
+        break if x == false
+      end
+    end
+  end
+
+  def test_exception_zerodivide
+    _test_mode(BigDecimal::EXCEPTION_ZERODIVIDE) { 1 / BigDecimal.new("0") }
+    _test_mode(BigDecimal::EXCEPTION_ZERODIVIDE) { -1 / BigDecimal.new("0") }
+  end
+
+  def test_round_up
+    n4 = BigDecimal.new("4") # n4 / 9 = 0.44444...
+    n5 = BigDecimal.new("5") # n5 / 9 = 0.55555...
+    n6 = BigDecimal.new("6") # n6 / 9 = 0.66666...
+    m4, m5, m6 = -n4, -n5, -n6
+    n2h = BigDecimal.new("2.5")
+    n3h = BigDecimal.new("3.5")
+    m2h, m3h = -n2h, -n3h
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_UP)
+    assert_operator(n4, :<, n4 / 9 * 9)
+    assert_operator(n5, :<, n5 / 9 * 9)
+    assert_operator(n6, :<, n6 / 9 * 9)
+    assert_operator(m4, :>, m4 / 9 * 9)
+    assert_operator(m5, :>, m5 / 9 * 9)
+    assert_operator(m6, :>, m6 / 9 * 9)
+    assert_equal(3, n2h.round)
+    assert_equal(4, n3h.round)
+    assert_equal(-3, m2h.round)
+    assert_equal(-4, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_DOWN)
+    assert_operator(n4, :>, n4 / 9 * 9)
+    assert_operator(n5, :>, n5 / 9 * 9)
+    assert_operator(n6, :>, n6 / 9 * 9)
+    assert_operator(m4, :<, m4 / 9 * 9)
+    assert_operator(m5, :<, m5 / 9 * 9)
+    assert_operator(m6, :<, m6 / 9 * 9)
+    assert_equal(2, n2h.round)
+    assert_equal(3, n3h.round)
+    assert_equal(-2, m2h.round)
+    assert_equal(-3, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_HALF_UP)
+    assert_operator(n4, :>, n4 / 9 * 9)
+    assert_operator(n5, :<, n5 / 9 * 9)
+    assert_operator(n6, :<, n6 / 9 * 9)
+    assert_operator(m4, :<, m4 / 9 * 9)
+    assert_operator(m5, :>, m5 / 9 * 9)
+    assert_operator(m6, :>, m6 / 9 * 9)
+    assert_equal(3, n2h.round)
+    assert_equal(4, n3h.round)
+    assert_equal(-3, m2h.round)
+    assert_equal(-4, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_HALF_DOWN)
+    assert_operator(n4, :>, n4 / 9 * 9)
+    assert_operator(n5, :>, n5 / 9 * 9)
+    assert_operator(n6, :<, n6 / 9 * 9)
+    assert_operator(m4, :<, m4 / 9 * 9)
+    assert_operator(m5, :<, m5 / 9 * 9)
+    assert_operator(m6, :>, m6 / 9 * 9)
+    assert_equal(2, n2h.round)
+    assert_equal(3, n3h.round)
+    assert_equal(-2, m2h.round)
+    assert_equal(-3, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_HALF_EVEN)
+    assert_operator(n4, :>, n4 / 9 * 9)
+    assert_operator(n5, :<, n5 / 9 * 9)
+    assert_operator(n6, :<, n6 / 9 * 9)
+    assert_operator(m4, :<, m4 / 9 * 9)
+    assert_operator(m5, :>, m5 / 9 * 9)
+    assert_operator(m6, :>, m6 / 9 * 9)
+    assert_equal(2, n2h.round)
+    assert_equal(4, n3h.round)
+    assert_equal(-2, m2h.round)
+    assert_equal(-4, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_CEILING)
+    assert_operator(n4, :<, n4 / 9 * 9)
+    assert_operator(n5, :<, n5 / 9 * 9)
+    assert_operator(n6, :<, n6 / 9 * 9)
+    assert_operator(m4, :<, m4 / 9 * 9)
+    assert_operator(m5, :<, m5 / 9 * 9)
+    assert_operator(m6, :<, m6 / 9 * 9)
+    assert_equal(3, n2h.round)
+    assert_equal(4, n3h.round)
+    assert_equal(-2, m2h.round)
+    assert_equal(-3, m3h.round)
+
+    BigDecimal.mode(BigDecimal::ROUND_MODE, BigDecimal::ROUND_FLOOR)
+    assert_operator(n4, :>, n4 / 9 * 9)
+    assert_operator(n5, :>, n5 / 9 * 9)
+    assert_operator(n6, :>, n6 / 9 * 9)
+    assert_operator(m4, :>, m4 / 9 * 9)
+    assert_operator(m5, :>, m5 / 9 * 9)
+    assert_operator(m6, :>, m6 / 9 * 9)
+    assert_equal(2, n2h.round)
+    assert_equal(3, n3h.round)
+    assert_equal(-3, m2h.round)
+    assert_equal(-4, m3h.round)
+  end
+
+  def test_zero_p
+    assert_equal(true, BigDecimal.new("0").zero?)
+    assert_equal(false, BigDecimal.new("1").zero?)
+  end
+
+  def test_nonzero_p
+    assert_equal(nil, BigDecimal.new("0").nonzero?)
+    assert_equal(BigDecimal.new("1"), BigDecimal.new("1").nonzero?)
+  end
+
+  def test_double_fig
+    assert_kind_of(Integer, BigDecimal.double_fig)
+  end
+
+  def test_cmp
+    n1 = BigDecimal.new("1")
+    n2 = BigDecimal.new("2")
+    assert_equal( 0, n1 <=> n1)
+    assert_equal( 1, n2 <=> n1)
+    assert_equal(-1, n1 <=> n2)
+    assert_operator(n1, :==, n1)
+    assert_operator(n1, :!=, n2)
+    assert_operator(n1, :<, n2)
+    assert_operator(n1, :<=, n1)
+    assert_operator(n1, :<=, n2)
+    assert_operator(n2, :>, n1)
+    assert_operator(n2, :>=, n1)
+    assert_operator(n1, :>=, n1)
+
+    assert_operator(BigDecimal.new("-0"), :==, BigDecimal.new("0"))
+    assert_operator(BigDecimal.new("0"), :<, BigDecimal.new("1"))
+    assert_operator(BigDecimal.new("1"), :>, BigDecimal.new("0"))
+    assert_operator(BigDecimal.new("1"), :>, BigDecimal.new("-1"))
+    assert_operator(BigDecimal.new("-1"), :<, BigDecimal.new("1"))
+    assert_operator(BigDecimal.new((2**100).to_s), :>, BigDecimal.new("1"))
+    assert_operator(BigDecimal.new("1"), :<, BigDecimal.new((2**100).to_s))
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    inf = BigDecimal.new("Infinity")
+    assert_operator(inf, :>, 1)
+    assert_operator(1, :<, inf)
+  end
+
+  def test_cmp_corece
+    n1 = BigDecimal.new("1")
+    n2 = BigDecimal.new("2")
+    o1 = Object.new; def o1.coerce(x); [x, BigDecimal.new("1")]; end
+    o2 = Object.new; def o2.coerce(x); [x, BigDecimal.new("2")]; end
+    assert_equal( 0, n1 <=> o1)
+    assert_equal( 1, n2 <=> o1)
+    assert_equal(-1, n1 <=> o2)
+    assert_operator(n1, :==, o1)
+    assert_operator(n1, :!=, o2)
+    assert_operator(n1, :<, o2)
+    assert_operator(n1, :<=, o1)
+    assert_operator(n1, :<=, o2)
+    assert_operator(n2, :>, o1)
+    assert_operator(n2, :>=, o1)
+    assert_operator(n1, :>=, 1)
+  end
+
+  def test_cmp_bignum
+    assert_operator(BigDecimal.new((2**100).to_s), :==, 2**100)
+  end
+
+  def test_cmp_data
+    d = Time.now; def d.coerce(x); [x, x]; end
+    assert_operator(BigDecimal.new((2**100).to_s), :==, d)
+  end
+
+  def test_induced_from
+    assert_instance_of(BigDecimal, BigDecimal.induced_from(1))
+    assert_raise(TypeError) do
+      BigDecimal.induced_from(Time.now)
+    end
+  end
+
+  def test_precs
+    a = BigDecimal.new("1").precs
+    assert_instance_of(Array, a)
+    assert_equal(2, a.size)
+    assert_kind_of(Integer, a[0])
+    assert_kind_of(Integer, a[1])
+  end
+
+  def test_hash
+    a = []
+    x = BigDecimal.new("1")
+    10.times { a << x *= 10 }
+    h = {}
+    a.each_with_index {|x, i| h[x] = i }
+    a.each_with_index do |x, i|
+      assert_equal(i, h[x])
+    end
+  end
+
+  def test_marshal
+    s = Marshal.dump(BigDecimal("1", 1))
+    assert_equal(BigDecimal("1", 1), Marshal.load(s))
+
+    # corrupt data
+    s = s.gsub(/BigDecimal.*\z/m) {|x| x.gsub(/\d/m, "-") }
+    assert_raise(TypeError) { Marshal.load(s) }
+  end
+
+  def test_finite_infinite_nan
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+
+    x = BigDecimal.new("0")
+    assert_equal(true, x.finite?)
+    assert_equal(nil, x.infinite?)
+    assert_equal(false, x.nan?)
+    y = 1 / x
+    assert_equal(false, y.finite?)
+    assert_equal(1, y.infinite?)
+    assert_equal(false, y.nan?)
+    y = -1 / x
+    assert_equal(false, y.finite?)
+    assert_equal(-1, y.infinite?)
+    assert_equal(false, y.nan?)
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    y = 0 / x
+    assert_equal(false, y.finite?)
+    assert_equal(nil, y.infinite?)
+    assert_equal(true, y.nan?)
+  end
+
+  def test_to_i
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+
+    x = BigDecimal.new("0")
+    assert_kind_of(Integer, x.to_i)
+    assert_equal(0, x.to_i)
+    assert_nil(( 1 / x).to_i)
+    assert_nil((-1 / x).to_i)
+    assert_nil(( 0 / x).to_i)
+    x = BigDecimal.new("1")
+    assert_equal(1, x.to_i)
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(2**100, x.to_i)
+  end
+
+  def test_to_f
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+
+    x = BigDecimal.new("0")
+    assert_instance_of(Float, x.to_f)
+    assert_equal(0.0, x.to_f)
+    assert_equal( 1.0 / 0.0, ( 1 / x).to_f)
+    assert_equal(-1.0 / 0.0, (-1 / x).to_f)
+    assert_equal(true, ( 0 / x).to_f.nan?)
+    x = BigDecimal.new("1")
+    assert_equal(1.0, x.to_f)
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal((2**100).to_f, x.to_f)
+    x = BigDecimal.new("1" + "0" * 10000)
+    assert_equal(0, BigDecimal.new("-0").to_f)
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, true)
+    assert_raise(FloatDomainError) { x.to_f }
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    assert_kind_of(Float,   x .to_f)
+    assert_kind_of(Float, (-x).to_f)
+  end
+
+  def test_coerce
+    a, b = BigDecimal.new("1").coerce(1.0)
+    assert_instance_of(Float, a)
+    assert_instance_of(Float, b)
+  end
+
+  def test_uplus
+    x = BigDecimal.new("1")
+    assert_equal(x, x.send(:+@))
+  end
+
+  def test_add
+    x = BigDecimal.new("1")
+    assert_equal(BigDecimal.new("2"), x + x)
+    assert_equal(1, BigDecimal.new("0") + 1)
+    assert_equal(1, x + 0)
+
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (BigDecimal.new("0") + 0).sign)
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (BigDecimal.new("-0") + 0).sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_ZERO, (BigDecimal.new("-0") + BigDecimal.new("-0")).sign)
+
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(BigDecimal.new((2**100+1).to_s), x + 1)
+  end
+
+  def test_sub
+    x = BigDecimal.new("1")
+    assert_equal(BigDecimal.new("0"), x - x)
+    assert_equal(-1, BigDecimal.new("0") - 1)
+    assert_equal(1, x - 0)
+
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (BigDecimal.new("0") - 0).sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_ZERO, (BigDecimal.new("-0") - 0).sign)
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (BigDecimal.new("-0") - BigDecimal.new("-0")).sign)
+
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(BigDecimal.new((2**100-1).to_s), x - 1)
+  end
+
+  def test_mult
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(BigDecimal.new((2**100 * 3).to_s), (x * 3).to_i)
+    assert_equal(x, (x * 1).to_i)
+    assert_equal(x, (BigDecimal("1") * x).to_i)
+    assert_equal(BigDecimal.new((2**200).to_s), (x * x).to_i)
+  end
+
+  def test_div
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(BigDecimal.new((2**100 / 3).to_s), (x / 3).to_i)
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (BigDecimal.new("0") / 1).sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_ZERO, (BigDecimal.new("-0") / 1).sign)
+    assert_equal(2, BigDecimal.new("2") / 1)
+    assert_equal(-2, BigDecimal.new("2") / -1)
+  end
+
+  def test_mod
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(1, x % 3)
+    assert_equal(2, (-x) % 3)
+    assert_equal(-2, x % -3)
+    assert_equal(-1, (-x) % -3)
+  end
+
+  def test_remainder
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(1, x.remainder(3))
+    assert_equal(-1, (-x).remainder(3))
+    assert_equal(1, x.remainder(-3))
+    assert_equal(-1, (-x).remainder(-3))
+  end
+
+  def test_divmod
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal([(x / 3).floor, 1], x.divmod(3))
+    assert_equal([(-x / 3).floor, 2], (-x).divmod(3))
+
+    assert_equal([0, 0], BigDecimal.new("0").divmod(2))
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    a, b = BigDecimal.new("0").divmod(0)
+    assert_equal(true, a.nan?)
+    assert_equal(true, b.nan?)
+  end
+
+  def test_add_bigdecimal
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(3000000000000000000000000000000, x.add(x, 1))
+    assert_equal(2500000000000000000000000000000, x.add(x, 2))
+    assert_equal(2540000000000000000000000000000, x.add(x, 3))
+  end
+
+  def test_sub_bigdecimal
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(1000000000000000000000000000000, x.sub(1, 1))
+    assert_equal(1300000000000000000000000000000, x.sub(1, 2))
+    assert_equal(1270000000000000000000000000000, x.sub(1, 3))
+  end
+
+  def test_mult_bigdecimal
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(4000000000000000000000000000000, x.mult(3, 1))
+    assert_equal(3800000000000000000000000000000, x.mult(3, 2))
+    assert_equal(3800000000000000000000000000000, x.mult(3, 3))
+  end
+
+  def test_div_bigdecimal
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(422550200076076467165567735125, x.div(3))
+    assert_equal(400000000000000000000000000000, x.div(3, 1))
+    assert_equal(420000000000000000000000000000, x.div(3, 2))
+    assert_equal(423000000000000000000000000000, x.div(3, 3))
+  end
+
+  def test_abs_bigdecimal
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(1267650600228229401496703205376, x.abs)
+    x = BigDecimal.new("-" + (2**100).to_s)
+    assert_equal(1267650600228229401496703205376, x.abs)
+    x = BigDecimal.new("0")
+    assert_equal(0, x.abs)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    x = BigDecimal.new("NaN")
+    assert_equal(true, x.abs.nan?)
+  end
+
+  def test_sqrt_bigdecimal
+    x = BigDecimal.new("0.09")
+    assert_in_delta(0.3, x.sqrt(1), 0.001)
+    x = BigDecimal.new((2**100).to_s)
+    assert_equal(1125899906842624, x.sqrt(1))
+    assert_equal(1125899906842624, x.sqrt(2))
+    assert_equal(1125899906842624, x.sqrt(3)) # I don't understand the meaning of argument...
+    x = BigDecimal.new("-" + (2**100).to_s)
+    assert_raise(FloatDomainError) { x.sqrt(1) }
+    x = BigDecimal.new((2**200).to_s)
+    assert_equal(2**100, x.sqrt(1))
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    assert_raise(FloatDomainError) { BigDecimal.new("NaN").sqrt(1) }
+
+    assert_equal(0, BigDecimal.new("0").sqrt(1))
+    assert_equal(1, BigDecimal.new("1").sqrt(1))
+  end
+
+  def test_fix
+    x = BigDecimal.new("1.1")
+    assert_equal(1, x.fix)
+  end
+
+  def test_frac
+    x = BigDecimal.new("1.1")
+    assert_equal(0.1, x.frac)
+    assert_equal(0.1, BigDecimal.new("0.1").frac)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    assert_equal(true, BigDecimal.new("NaN").frac.nan?)
+  end
+
+  def test_round
+    assert_equal(3, BigDecimal.new("3.14159").round)
+    assert_equal(9, BigDecimal.new("8.7").round)
+    assert_equal(3.142, BigDecimal.new("3.14159").round(3))
+    assert_equal(13300.0, BigDecimal.new("13345.234").round(-2))
+
+    x = BigDecimal.new("111.111")
+    assert_equal(111    , x.round)
+    assert_equal(111.1  , x.round(1))
+    assert_equal(111.11 , x.round(2))
+    assert_equal(111.111, x.round(3))
+    assert_equal(111.111, x.round(4))
+    assert_equal(110    , x.round(-1))
+    assert_equal(100    , x.round(-2))
+    assert_equal(  0    , x.round(-3))
+    assert_equal(  0    , x.round(-4))
+
+    x = BigDecimal.new("2.5")
+    assert_equal(3, x.round(0, BigDecimal::ROUND_UP))
+    assert_equal(2, x.round(0, BigDecimal::ROUND_DOWN))
+    assert_equal(3, x.round(0, BigDecimal::ROUND_HALF_UP))
+    assert_equal(2, x.round(0, BigDecimal::ROUND_HALF_DOWN))
+    assert_equal(2, x.round(0, BigDecimal::ROUND_HALF_EVEN))
+    assert_equal(3, x.round(0, BigDecimal::ROUND_CEILING))
+    assert_equal(2, x.round(0, BigDecimal::ROUND_FLOOR))
+    assert_raise(TypeError) { x.round(0, 256) }
+  end
+
+  def test_truncate
+    assert_equal(3, BigDecimal.new("3.14159").truncate)
+    assert_equal(8, BigDecimal.new("8.7").truncate)
+    assert_equal(3.141, BigDecimal.new("3.14159").truncate(3))
+    assert_equal(13300.0, BigDecimal.new("13345.234").truncate(-2))
+  end
+
+  def test_floor
+    assert_equal(3, BigDecimal.new("3.14159").floor)
+    assert_equal(-10, BigDecimal.new("-9.1").floor)
+    assert_equal(3.141, BigDecimal.new("3.14159").floor(3))
+    assert_equal(13300.0, BigDecimal.new("13345.234").floor(-2))
+  end
+
+  def test_ceil
+    assert_equal(4, BigDecimal.new("3.14159").ceil)
+    assert_equal(-9, BigDecimal.new("-9.1").ceil)
+    assert_equal(3.142, BigDecimal.new("3.14159").ceil(3))
+    assert_equal(13400.0, BigDecimal.new("13345.234").ceil(-2))
+  end
+
+  def test_to_s
+    assert_equal('-123.45678 90123 45678 9', BigDecimal.new('-123.45678901234567890').to_s('5F'))
+    assert_equal('+123.45678901 23456789', BigDecimal.new('123.45678901234567890').to_s('+8F'))
+    assert_equal(' 123.4567890123456789', BigDecimal.new('123.45678901234567890').to_s(' F'))
+    assert_equal('0.1234567890123456789E3', BigDecimal.new('123.45678901234567890').to_s)
+    assert_equal('0.12345 67890 12345 6789E3', BigDecimal.new('123.45678901234567890').to_s(5))
+  end
+
+  def test_split
+    x = BigDecimal.new('-123.45678901234567890')
+    assert_equal([-1, "1234567890123456789", 10, 3], x.split)
+    assert_equal([1, "0", 10, 0], BigDecimal.new("0").split)
+    assert_equal([-1, "0", 10, 0], BigDecimal.new("-0").split)
+
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    assert_equal([0, "NaN", 10, 0], BigDecimal.new("NaN").split)
+    assert_equal([1, "Infinity", 10, 0], BigDecimal.new("Infinity").split)
+    assert_equal([-1, "Infinity", 10, 0], BigDecimal.new("-Infinity").split)
+  end
+
+  def test_exponent
+    x = BigDecimal.new('-123.45678901234567890')
+    assert_equal(3, x.exponent)
+  end
+
+  def test_inspect
+    x = BigDecimal.new("1234.5678")
+    assert_match(/^#<BigDecimal:[0-9a-f]+,'0.12345678E4',8\(12\)>$/, x.inspect)
+  end
+
+  def test_power
+    x = BigDecimal.new("3")
+    assert_equal(81, x ** 4)
+    assert_equal(1.0/81, x ** -4)
+    assert_equal(1, x ** 0)
+    assert_raise(TypeError) { x ** x }
+    assert_equal(0, BigDecimal.new("0") ** 4)
+    assert_equal(1, BigDecimal.new("0") ** 0)
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    assert_equal(BigDecimal.new("Infinity"), BigDecimal.new("0") ** -1)
+    assert_equal(BigDecimal.new("-Infinity"), BigDecimal.new("-0") ** -1)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    assert_equal(true, (BigDecimal.new("NaN") ** 1).nan?)
+    assert_equal(true, (BigDecimal.new("Infinity") ** 1).nan?) # OK?
+  end
+
+  def test_limit
+    BigDecimal.limit(1)
+    x = BigDecimal.new("3")
+    assert_equal(90, x ** 4) # OK? must it be 80?
+    # 3 * 3 * 3 * 3 = 10 * 3 * 3 = 30 * 3 = 90 ???
+    assert_raise(ArgumentError) { BigDecimal.limit(-1) }
+  end
+
+  def test_sign
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, BigDecimal.new("0").sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_ZERO, BigDecimal.new("-0").sign)
+    assert_equal(BigDecimal::SIGN_POSITIVE_FINITE, BigDecimal.new("1").sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_FINITE, BigDecimal.new("-1").sign)
+    assert_equal(BigDecimal::SIGN_POSITIVE_INFINITE, (BigDecimal.new("1") / 0).sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_INFINITE, (BigDecimal.new("-1") / 0).sign)
+    assert_equal(BigDecimal::SIGN_NaN, (BigDecimal.new("0") / 0).sign)
+  end
+
+  def test_inf
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    inf = BigDecimal.new("Infinity")
+
+    assert_equal(inf, inf + inf)
+    assert_equal(true, (inf + (-inf)).nan?)
+    assert_equal(true, (inf - inf).nan?)
+    assert_equal(inf, inf - (-inf))
+    assert_equal(inf, inf * inf)
+    assert_equal(true, (inf / inf).nan?)
+
+    assert_equal(inf, inf + 1)
+    assert_equal(inf, inf - 1)
+    assert_equal(inf, inf * 1)
+    assert_equal(true, (inf * 0).nan?)
+    assert_equal(inf, inf / 1)
+
+    assert_equal(inf, 1 + inf)
+    assert_equal(-inf, 1 - inf)
+    assert_equal(inf, 1 * inf)
+    assert_equal(-inf, -1 * inf)
+    assert_equal(true, (0 * inf).nan?)
+    assert_equal(BigDecimal::SIGN_POSITIVE_ZERO, (1 / inf).sign)
+    assert_equal(BigDecimal::SIGN_NEGATIVE_ZERO, (-1 / inf).sign)
+  end
+
+  def test_to_special_string
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    BigDecimal.mode(BigDecimal::EXCEPTION_NaN, false)
+    nan = BigDecimal.new("NaN")
+    assert_equal("NaN", nan.to_s)
+    inf = BigDecimal.new("Infinity")
+    assert_equal("Infinity", inf.to_s)
+    assert_equal(" Infinity", inf.to_s(" "))
+    assert_equal("+Infinity", inf.to_s("+"))
+    assert_equal("-Infinity", (-inf).to_s)
+    pzero = BigDecimal.new("0")
+    assert_equal("0.0", pzero.to_s)
+    assert_equal(" 0.0", pzero.to_s(" "))
+    assert_equal("+0.0", pzero.to_s("+"))
+    assert_equal("-0.0", (-pzero).to_s)
+  end
+
+  def test_to_string
+    assert_equal("0.01", BigDecimal("0.01").to_s("F"))
+    s = "0." + "0" * 100 + "1"
+    assert_equal(s, BigDecimal(s).to_s("F"))
+    s = "1" + "0" * 100 + ".0"
+    assert_equal(s, BigDecimal(s).to_s("F"))
+  end
+
+  def test_ctov
+    assert_equal(0.1, BigDecimal.new("1E-1"))
+    assert_equal(10, BigDecimal.new("1E+1"))
+    assert_equal(1, BigDecimal.new("+1"))
+    BigDecimal.mode(BigDecimal::EXCEPTION_OVERFLOW, false)
+    assert_equal(0, BigDecimal.new("1E1" + "0" * 100)) # OK? must it be inf?
+  end
+end