Move spec/rubyspec to spec/ruby for consistency

* Other ruby implementations use the spec/ruby directory.
  [Misc #13792] [ruby-core:82287]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@59979 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

spec/ruby/library/bigdecimal/shared/power.rb

@@ -0,0 +1,72 @@
+require 'bigdecimal'
+
+describe :bigdecimal_power, shared: true do
+  it "powers of self" do
+    e3_minus = BigDecimal("3E-20001")
+    e3_minus_power_2 = BigDecimal("9E-40002")
+    e3_plus = BigDecimal("3E20001")
+    e2_plus = BigDecimal("2E40001")
+    e5_minus = BigDecimal("5E-40002")
+    e = BigDecimal("1.00000000000000000000123456789")
+    one = BigDecimal("1")
+    ten = BigDecimal("10")
+    # The tolerance is dependent upon the size of BASE_FIG
+    tolerance = BigDecimal("1E-70")
+    ten_powers = BigDecimal("1E10000")
+    pi = BigDecimal("3.14159265358979")
+    e3_minus.send(@method, 2).should == e3_minus_power_2
+    e3_plus.send(@method, 0).should == 1
+    e3_minus.send(@method, 1).should == e3_minus
+    e2_plus.send(@method, -1).should == e5_minus
+    e2_plus.send(@method, -1).should == e5_minus.power(1)
+    (e2_plus.send(@method, -1) * e5_minus.send(@method, -1)).should == 1
+    e.send(@method, 2).should == e * e
+    e.send(@method, -1).should be_close(one.div(e, 120), tolerance)
+    ten.send(@method, 10000).should == ten_powers
+    pi.send(@method, 10).should be_close(Math::PI ** 10, TOLERANCE)
+  end
+
+  it "powers of 1 equal 1" do
+    one = BigDecimal("1")
+    one.send(@method, 0).should == 1
+    one.send(@method, 1).should == 1
+    one.send(@method, 10).should == 1
+    one.send(@method, -10).should == 1
+  end
+
+  it "0 to power of 0 is 1" do
+    zero = BigDecimal("0")
+    zero.send(@method, 0).should == 1
+  end
+
+  it "0 to powers < 0 is Infinity" do
+    zero = BigDecimal("0")
+    infinity = BigDecimal("Infinity")
+    zero.send(@method, -10).should == infinity
+    zero.send(@method, -1).should == infinity
+  end
+
+  it "other powers of 0 are 0" do
+    zero = BigDecimal("0")
+    zero.send(@method, 1).should == 0
+    zero.send(@method, 10).should == 0
+  end
+
+  it "returns NaN if self is NaN" do
+    BigDecimal("NaN").send(@method, -5).nan?.should == true
+    BigDecimal("NaN").send(@method, 5).nan?.should == true
+  end
+
+  it "returns 0.0 if self is infinite and argument is negative" do
+    BigDecimal("Infinity").send(@method, -5).should == 0
+    BigDecimal("-Infinity").send(@method, -5).should == 0
+  end
+
+  it "returns infinite if self is infinite and argument is positive" do
+    infinity = BigDecimal("Infinity")
+    BigDecimal("Infinity").send(@method, 4).should == infinity
+    BigDecimal("-Infinity").send(@method, 4).should == infinity
+    BigDecimal("Infinity").send(@method, 5).should == infinity
+    BigDecimal("-Infinity").send(@method, 5).should == -infinity
+  end
+end