Initial import of BigDecimal tests.

test/test/spec/nsdecimal_spec.rb

@@ -9,3 +9,133 @@ describe "NSDecimal" do
     NSDecimalString(ptr, nil).should == dn.stringValue
   end
 end
+
+describe 'BigDecimal' do
+  it 'is an alias for NSDecimalNumber' do
+    BigDecimal.should == NSDecimalNumber
+  end
+
+  it 'can be created with a string' do
+    bd = BigDecimal.new('  0.123456789123456789END')
+    #bd = BigDecimal.new('0.123456789123456789')
+    bd.class.should == BigDecimal
+    bd.inspect.should == '0.123456789123456789'
+  end
+
+  xit 'can be created with an integer' do
+    bd = BigDecimal.new(42)
+    bd.class.should == BigDecimal
+    bd.inspect.should == '42'
+  end
+
+  xit 'can be created with a float' do
+    bd = BigDecimal.new(0.1)
+    bd.class.should == BigDecimal
+    bd.inspect.should == '0.1'
+  end
+
+  xit 'can be created with a BigDecimal' do
+    bd = BigDecimal.new(BigDecimal.new(42))
+    bd.class.should == BigDecimal
+    bd.inspect.should == '42'
+  end
+
+  it 'returns whether or not it is zero' do
+    BigDecimal.new('0.00000000000000000').should.be.zero
+    BigDecimal.new('0.00000000000000000').should.not.be.nonzero
+    BigDecimal.new('0.00000000000000001').should.be.nonzero
+    BigDecimal.new('0.00000000000000001').should.not.be.zero
+  end
+
+  it 'returns whether or not is a number' do
+    (BigDecimal.new('0') / BigDecimal.new('0')).should.be.nan
+    (BigDecimal.new('1') / BigDecimal.new('1')).should.not.be.nan
+  end
+
+  it 'returns wether or not it is infinite' do
+    (BigDecimal.new('1') / BigDecimal.new('0')).infinite?.should == 1
+    (BigDecimal.new('-1') / BigDecimal.new('0')).infinite?.should == -1
+    (BigDecimal.new('1') / BigDecimal.new('1')).infinite?.should == nil
+  end
+
+  it 'returns wether or not it is finite' do
+    (BigDecimal.new('1') / BigDecimal.new('1')).should.be.finite
+    # NaN
+    (BigDecimal.new('0') / BigDecimal.new('0')).should.not.be.finite
+    # Infinity
+    (BigDecimal.new('1') / BigDecimal.new('0')).should.not.be.finite
+    (BigDecimal.new('-1') / BigDecimal.new('0')).should.not.be.finite
+  end
+
+  it 'can sum' do
+    sum = BigDecimal.new('0')
+    10000.times do
+      sum = sum + BigDecimal.new('0.0001')
+    end
+    sum.inspect.should == '1'
+  end
+
+  it 'can subtract' do
+    sum = BigDecimal.new('1')
+    10000.times do
+      sum = sum - BigDecimal.new('0.0001')
+    end
+    sum.inspect.should == '0'
+  end
+
+  it 'can multiply' do
+    sum = BigDecimal.new('0.0001')
+    10.times do
+      sum = sum * BigDecimal.new('2')
+    end
+    sum.inspect.should == '0.1024'
+  end
+
+  it 'can divide' do
+    sum = BigDecimal.new('0.1024')
+    10.times do
+      sum = sum / BigDecimal.new('2')
+    end
+    sum.inspect.should == '0.0001'
+  end
+
+  it 'can raise to the power N' do
+    (BigDecimal.new('0.0003') ** 2).inspect.should == '0.00000009'
+  end
+
+  it 'is comparable' do
+    low  = BigDecimal.new('0.0000001')
+    high = BigDecimal.new('0.0000002')
+
+    low.should == low
+    low.should != high
+
+    low.should >= low
+    low.should <= low
+
+    low.should <= high
+    high.should >= low
+
+    low.should < high
+    high.should > low
+  end
+
+  it 'can be passed to Objective-C APIs transperantly' do
+    string = '0.123456789123456789'
+    formatter = NSNumberFormatter.new
+    formatter.alwaysShowsDecimalSeparator = true
+    formatter.minimumIntegerDigits = 1
+    formatter.minimumFractionDigits = string.split('.').last.length
+
+    formatter.stringFromNumber(BigDecimal.new(string)).should == string
+  end
+
+  # TODO when we receive a number from an Objective-C API we must
+  #      ensure to keep it a NSDecimalNumber
+  xit 'can be passed from Objective-C APIs transperantly' do
+    string = '0.123456789123456789'
+    formatter = NSNumberFormatter.new
+    formatter.generatesDecimalNumbers = true
+    formatter.numberFromString(string).should == BigDecimal.new(string)
+  end
+end