Fix bigdecimal spec (#1290)

Fix for new feature BigDecimal(float).
Fix assertion of BigMath.log not to expect incorrect random digits to be appended.
Fix assertion of too-strict precision and assertion that expecting precision to be too loose.
Fix divmod, modulo and remainder assertion which was expecting a bug inconsistent with Float as a specification.
Remove coerce expectation to add/sub/mult which was dropped because of a bug, and never implemented correctly in BigDecmal.

Author: tompng

library/bigdecimal/BigDecimal_spec.rb

@@ -156,8 +156,10 @@
     BigDecimal("-12345.6E-1").should == -reference
   end
 
-  it "raises ArgumentError when Float is used without precision" do
-    -> { BigDecimal(1.0) }.should raise_error(ArgumentError)
+  version_is BigDecimal::VERSION, "3.3.0" do
+    it "allows Float without precision" do
+      BigDecimal(1.2).should == BigDecimal("1.2")
+    end
   end
 
   it "returns appropriate BigDecimal zero for signed zero" do
@@ -259,8 +261,8 @@ def to_s; "cheese"; end
     end
 
     it "produces the expected result" do
-      @c.should == BigDecimal("-0.666667e-9")
-      @c.to_s.should == "-0.666667e-9"
+      @c.round(15).should == BigDecimal("-0.666667e-9")
+      @c.round(15).to_s.should == "-0.666667e-9"
     end
 
     it "produces the correct class for other arithmetic operators" do

library/bigdecimal/add_spec.rb

@@ -73,14 +73,6 @@
 #    BigDecimal("0.88").add(0.0, 1).should == BigDecimal("0.9")
 #  end
 
-  describe "with Object" do
-    it "tries to coerce the other operand to self" do
-      object = mock("Object")
-      object.should_receive(:coerce).with(@frac_3).and_return([@frac_3, @frac_4])
-      @frac_3.add(object, 1).should == BigDecimal("0.1E16")
-    end
-  end
-
   describe "with Rational" do
     it "produces a BigDecimal" do
       (@three + Rational(500, 2)).should == BigDecimal("0.253e3")

library/bigdecimal/core_spec.rb

@@ -20,9 +20,12 @@
 
   describe "BigDecimal#log" do
     it "handles high-precision Rational arguments" do
-      result = BigDecimal('0.22314354220170971436137296411949880462556361100856391620766259404746040597133837784E0')
+      # log(BigDecimal(r, 50), 50)
+      result1 = BigDecimal('0.22314354220170971436137296411949880462556361100856e0')
+      # log(BigDecimal(r, 1000), 50)
+      result2 = BigDecimal('0.22314354220170971436137296411949880462556361100853e0')
       r = Rational(1_234_567_890, 987_654_321)
-      BigMath.log(r, 50).should == result
+      [result1, result2].should include(BigMath.log(r, 50).mult(1, 50))
     end
   end
 

library/bigdecimal/divmod_spec.rb

@@ -154,12 +154,19 @@ class BigDecimal
     end
   end
 
-  it "returns an array of zero and the dividend if the divisor is Infinity" do
-    @regular_vals.each do |val|
-      array = val.divmod(@infinity)
-      array.length.should == 2
-      array[0].should == @zero
-      array[1].should == val
+  version_is BigDecimal::VERSION, "3.3.0" do
+    it "returns an array of zero and the dividend or minus one and Infinity if the divisor is Infinity" do
+      @regular_vals.each do |val|
+        array = val.divmod(@infinity)
+        array.length.should == 2
+        if val >= 0
+          array[0].should == @zero
+          array[1].should == val
+        else
+          array[0].should == @one_minus
+          array[1].should == @infinity
+        end
+      end
     end
   end
 

library/bigdecimal/mult_spec.rb

@@ -21,12 +21,4 @@
     @e.mult(@one, 1).should be_close(@one, @tolerance)
     @e3_minus.mult(@one, 1).should be_close(0, @tolerance2)
   end
-
-  describe "with Object" do
-    it "tries to coerce the other operand to self" do
-      object = mock("Object")
-      object.should_receive(:coerce).with(@e3_minus).and_return([@e3_minus, @e3_plus])
-      @e3_minus.mult(object, 1).should == BigDecimal("9")
-    end
-  end
 end

library/bigdecimal/remainder_spec.rb

@@ -37,9 +37,11 @@
     @neg_int.remainder(@pos_frac).should == @neg_int - @pos_frac * (@neg_int / @pos_frac).truncate
   end
 
-  it "returns NaN used with zero" do
-    @mixed.remainder(@zero).should.nan?
-    @zero.remainder(@zero).should.nan?
+  version_is BigDecimal::VERSION, "3.3.0" do
+    it "raises ZeroDivisionError used with zero" do
+      -> { @mixed.remainder(@zero) }.should raise_error(ZeroDivisionError)
+      -> { @zero.remainder(@zero) }.should raise_error(ZeroDivisionError)
+    end
   end
 
   it "returns zero if used on zero" do

library/bigdecimal/shared/modulo.rb

@@ -101,10 +101,16 @@
     @infinity_minus.send(@method, @infinity).should.nan?
   end
 
-  it "returns the dividend if the divisor is Infinity" do
-    @one.send(@method, @infinity).should == @one
-    @one.send(@method, @infinity_minus).should == @one
-    @frac_2.send(@method, @infinity_minus).should == @frac_2
+  version_is BigDecimal::VERSION, "3.3.0" do
+    it "returns the dividend if the divisor is Infinity and signs are same" do
+      @one.send(@method, @infinity).should == @one
+      (-@frac_2).send(@method, @infinity_minus).should == -@frac_2
+    end
+
+    it "returns the divisor if the divisor is Infinity and signs are different" do
+      (-@one).send(@method, @infinity).should == @infinity
+      @frac_2.send(@method, @infinity_minus).should == @infinity_minus
+    end
   end
 
   it "raises TypeError if the argument cannot be coerced to BigDecimal" do

library/bigdecimal/shared/power.rb

@@ -10,8 +10,8 @@
     e = BigDecimal("1.00000000000000000000123456789")
     one = BigDecimal("1")
     ten = BigDecimal("10")
-    # The tolerance is dependent upon the size of BASE_FIG
-    tolerance = BigDecimal("1E-70")
+    # Accuracy is at least ndigits(== 30) + DOUBLE_FIG(== 16)
+    tolerance = BigDecimal("1E-46")
     ten_powers = BigDecimal("1E10000")
     pi = BigDecimal("3.14159265358979")
     e3_minus.send(@method, 2).should == e3_minus_power_2

library/bigdecimal/sub_spec.rb

@@ -35,14 +35,6 @@
     @frac_1.sub(@frac_1, 1000000).should == @zero
   end
 
-  describe "with Object" do
-    it "tries to coerce the other operand to self" do
-      object = mock("Object")
-      object.should_receive(:coerce).with(@frac_3).and_return([@frac_3, @frac_4])
-      @frac_3.sub(object, 1).should == BigDecimal("-0.9E15")
-    end
-  end
-
   describe "with Rational" do
     it "produces a BigDecimal" do
       (@three - Rational(500, 2)).should == BigDecimal('-0.247e3')