diff --git a/cexps.js b/cexps.js
index 8a41373..f996a65 100644
--- a/cexps.js
+++ b/cexps.js
@@ -102,7 +102,7 @@ var lessoreq = Primop("<=");
 var greatthan = Primop(">");
 var greatoreq = Primop(">=");
 var bang = Primop("!");
-var subscript = Protoype("subscript");
+var subscript = Primop("subscript");
 var ordof = Primop("ordof");
 var assign = Primop(":=");
 var unboxedassign = Primop("unboxedassign");
diff --git a/closure_conversion.js b/closure_conversion.js
index d8efe07..34a26d4 100644
--- a/closure_conversion.js
+++ b/closure_conversion.js
@@ -147,8 +147,6 @@ function test(src) {
   console.log(JSON.stringify(closure_convert_all(ast), null, 4));
 }
 
-test("(lambda a -> (+ a b c))");
-
 module.export = {
   test : test,
   closureConvert : closure_convert_all
diff --git a/test.js b/test.js
index 38d7b1a..7c254ac 100755
--- a/test.js
+++ b/test.js
@@ -1,4 +1,76 @@
 #!  /usr/bin/node
 
 var parser = require("./parse.js");
+var cexps = require("./cexps.js");
+var closures = require("./closure_conversion.js");
+var desugar = require("./desugar.js");
+var environments = require("./environments.js");
+var errors = require("./errors.js");
+var tokens = require("./tokenize.js");
+var tools = require("./tools.js");
+var typecheck = require("./typecheck.js");
+var _ = require("underscore");
+
 var qc = require("quickcheck");
+var assert = require("assert");
+
+
+/* my own generators */
+function arbArray(gen) {
+  return qc.arbArray(gen);
+}
+
+
+function arbPair(gen) {
+  return function() {
+    return [gen(), gen()];
+  };
+}
+
+function arbArrayofPairs() {
+  return arbArray(function() {
+    return arbArray(arbPair(qc.arbString));
+  });
+}
+
+function arbPairs() {
+  return arbArray(arbPair(qc.arbString));
+}
+
+
+/* Tests for misc tools */
+function emptyProp(xs) {
+  return (tools.empty(xs) === tools.empty(xs) &&
+          ((tools.empty(xs) === true) ||
+           (tools.empty(xs) === false)));
+}
+
+
+function dictProp(pairs) {
+  var dict = tools.dict(pairs);
+  return _.map(pairs,
+         function(pair) {
+           dict[pair[0]] === pair[1];
+         });
+}
+
+function extendProp(pair) {
+  if (pair.length < 2) {
+    // empty lists or lists with one item are undefined
+    // so just return true because extend can't handle them
+    return true;
+  }
+  var x = _.first(pair);
+  var y = _.first(_.rest(pair));
+  var extended = tools.extend(x,y);
+  return x.length + y.length === extended.length;
+}
+
+function toolsTests() {
+  assert.equal(true, tools.empty([]));
+  assert.equal(true, qc.forAll(dictProp, arbArrayofPairs));
+  assert.equal(true, qc.forAll(extendProp, arbPairs));
+}
+
+
+toolsTests();
diff --git a/tools.js b/tools.js
index bccb8b1..a20f399 100644
--- a/tools.js
+++ b/tools.js
@@ -41,21 +41,10 @@ function dict(pairs) {
   return o;
 }
 
-function flatten(xs) {
-  if (!(xs instanceof Array)) {
-    return xs;
-  }
-  if (xs.every(function (x) {
-    return !(x instanceof Array);
-  })) {
-    return xs;
-  }
-  return [].concat.apply([], xs);
-}
-
 function extend(xs, ys) {
-  xs.push.apply(xs, ys);
-  return xs;
+  var result = _.clone(xs);
+  result.push.apply(result, ys);
+  return result;
 }
 
 RegExp.escape= function(s) {