Fix warnings

Author: jhawthorn

test/test_encoder_compatibility.rb

@@ -50,7 +50,7 @@ def test_encode_float
 
     # Found via random test, this is the exact representation
     assert_compat 103876218730131.625
-    assert_compat -169986783765216.875
+    assert_compat(-169986783765216.875)
 
     0.upto(1023) do |e|
       assert_compat(2.0 ** e)

test/test_parser.rb

@@ -102,6 +102,6 @@ def test_parse_NaN_and_Infinity_allowed
 
     assert_predicate coder.load("NaN"), :nan?
     assert_equal Float::INFINITY, coder.load("Inf")
-    assert_equal -Float::INFINITY, coder.load("-Inf")
+    assert_equal(-Float::INFINITY, coder.load("-Inf"))
   end
 end