Silence some warnings about unused vars

test/engine_test.rb

@@ -1264,6 +1264,9 @@ HAML
     string.instance_variable_set("@var", "Instance variable")
     b = string.instance_eval do
       var = "Local variable"
+      # Silence unavoidable warning; Ruby doesn't know we're going to use this
+      # later.
+      nil if var
       binding
     end
 

test/filters_test.rb

@@ -84,14 +84,14 @@ class ErbFilterTest < MiniTest::Unit::TestCase
   test "should evaluate in the same context as Haml" do
     haml  = ":erb\n  <%= foo %>"
     html  = "bar\n"
-    scope = Object.new.instance_eval {foo = "bar"; binding}
+    scope = Object.new.instance_eval {foo = "bar"; nil if foo; binding}
     assert_equal(html, render(haml, :scope => scope))
   end
 end
 
 class JavascriptFilterTest < MiniTest::Unit::TestCase
   test "should interpolate" do
-    scope = Object.new.instance_eval {foo = "bar"; binding}
+    scope = Object.new.instance_eval {foo = "bar"; nil if foo; binding}
     haml  = ":javascript\n  \#{foo}"
     html  = render(haml, :scope => scope)
     assert_match(/bar/, html)