Add specs for RBIGNUM_SIGN

Author: eregon

spec/ruby/optional/capi/bignum_spec.rb

@@ -97,6 +97,16 @@ def ensure_bignum(n)
     end
   end
 
+  describe "RBIGNUM_SIGN" do
+    it "returns 1 for a positive Bignum" do
+      @s.RBIGNUM_SIGN(bignum_value(1)).should == 1
+    end
+
+    it "returns 0 for a negative Bignum" do
+      @s.RBIGNUM_SIGN(-bignum_value(1)).should == 0
+    end
+  end
+
   describe "rb_big_cmp" do
     it "compares a Bignum with a Bignum" do
       @s.rb_big_cmp(bignum_value, bignum_value(1)).should == -1

spec/ruby/optional/capi/ext/bignum_spec.c

@@ -31,6 +31,10 @@ static VALUE bignum_spec_rb_big2ulong(VALUE self, VALUE num) {
   return ULONG2NUM(rb_big2ulong(num));
 }
 
+static VALUE bignum_spec_RBIGNUM_SIGN(VALUE self, VALUE val) {
+  return INT2FIX(RBIGNUM_SIGN(val));
+}
+
 static VALUE bignum_spec_rb_big_cmp(VALUE self, VALUE x, VALUE y) {
   return rb_big_cmp(x, y);
 }
@@ -90,6 +94,7 @@ void Init_bignum_spec(void) {
   rb_define_method(cls, "rb_big2long", bignum_spec_rb_big2long, 1);
   rb_define_method(cls, "rb_big2str", bignum_spec_rb_big2str, 2);
   rb_define_method(cls, "rb_big2ulong", bignum_spec_rb_big2ulong, 1);
+  rb_define_method(cls, "RBIGNUM_SIGN", bignum_spec_RBIGNUM_SIGN, 1);
   rb_define_method(cls, "rb_big_cmp", bignum_spec_rb_big_cmp, 2);
   rb_define_method(cls, "rb_big_pack", bignum_spec_rb_big_pack, 1);
   rb_define_method(cls, "rb_big_pack_array", bignum_spec_rb_big_pack_array, 2);