diff --git a/test/checks-test.js b/test/checks-test.js
index eb3b453..39a7dea 100644
--- a/test/checks-test.js
+++ b/test/checks-test.js
@@ -1,4 +1,4 @@
-(function(global) {
+(function() {
 
 module("PEG.compiler.checks");
 
@@ -65,4 +65,4 @@ test("reports left recursion", function() {
   }
 });
 
-})(this);
+})();
diff --git a/test/compiler-test.js b/test/compiler-test.js
index 3c10657..ca5a16f 100644
--- a/test/compiler-test.js
+++ b/test/compiler-test.js
@@ -1,4 +1,4 @@
-(function(global) {
+(function() {
 
 module("PEG.compiler");
 
@@ -506,4 +506,4 @@ test("nested comments", function() {
   );
 });
 
-})(this);
+})();
diff --git a/test/parser-test.js b/test/parser-test.js
index 3754eac..8bccdb0 100644
--- a/test/parser-test.js
+++ b/test/parser-test.js
@@ -1,4 +1,4 @@
-(function(global) {
+(function() {
 
 module("PEG.parser");
 
@@ -589,4 +589,4 @@ test("parses whitespace", function() {
   parserParses('start =\u3000"abcd"', simpleGrammar);
 });
 
-})(this);
+})();
diff --git a/test/passes-test.js b/test/passes-test.js
index bb11531..4ae423f 100644
--- a/test/passes-test.js
+++ b/test/passes-test.js
@@ -1,4 +1,4 @@
-(function(global) {
+(function() {
 
 module("PEG.compiler.passes");
 
@@ -147,4 +147,4 @@ test("removes proxy rules", function() {
   }
 });
 
-})(this);
+})();