Suppress too big exponent warnings

spec/ruby/shared/rational/exponent.rb

@@ -105,14 +105,24 @@ describe :rational_exponent, shared: true do
     # Fails on linux due to pow() bugs in glibc: http://sources.redhat.com/bugzilla/show_bug.cgi?id=3866
     platform_is_not :linux do
       it "returns positive Infinity when self < -1" do
-        (Rational(-2) ** bignum_value).infinite?.should == 1
-        (Rational(-2) ** (bignum_value + 1)).infinite?.should == 1
-        (Rational(fixnum_min) ** bignum_value).infinite?.should == 1
+        -> {
+          (Rational(-2) ** bignum_value).infinite?.should == 1
+        }.should complain(/warning: in a\*\*b, b may be too big/)
+        -> {
+          (Rational(-2) ** (bignum_value + 1)).infinite?.should == 1
+        }.should complain(/warning: in a\*\*b, b may be too big/)
+        -> {
+          (Rational(fixnum_min) ** bignum_value).infinite?.should == 1
+        }.should complain(/warning: in a\*\*b, b may be too big/)
       end
 
       it "returns 0.0 when self is < -1 and the exponent is negative" do
-        (Rational(-2) ** -bignum_value).should eql(0.0)
-        (Rational(fixnum_min) ** -bignum_value).should eql(0.0)
+        -> {
+          (Rational(-2) ** -bignum_value).should eql(0.0)
+        }.should complain(/warning: in a\*\*b, b may be too big/)
+        -> {
+          (Rational(fixnum_min) ** -bignum_value).should eql(0.0)
+        }.should complain(/warning: in a\*\*b, b may be too big/)
       end
     end
   end