1 files changed, 2 insertions, 3 deletions
diff --git a/spec/ruby/library/matrix/divide_spec.rb b/spec/ruby/library/matrix/divide_spec.rb
index d656985f38..205bc5d892 100644
--- a/spec/ruby/library/matrix/divide_spec.rb
+++ b/spec/ruby/library/matrix/divide_spec.rb
@@ -14,13 +14,12 @@ describe "Matrix#/" do
     (@a / @b).should be_close_to_matrix([[2.5, -1.5], [1.5, -0.5]])
   end
 
-  conflicts_with :Prime do
+  # Guard against the Mathn library
+  guard -> { !defined?(Math.rsqrt) } do
     it "returns the result of dividing self by a Fixnum" do
       (@a / 2).should == Matrix[ [0, 1], [1, 2] ]
     end
-  end
 
-  conflicts_with :Prime do
     it "returns the result of dividing self by a Bignum" do
       (@a / bignum_value).should == Matrix[ [0, 0], [0, 0] ]
     end