diff --git a/test.js b/test.js
index 9a8ad00..746f10f 100644
--- a/test.js
+++ b/test.js
@@ -976,6 +976,30 @@ describe('xpath', () => {
         });
     });
 
+    describe('.parse()', () => {
+        it('should correctly set types on path steps', () => {
+            const parsed = xpath.parse('./my:*/my:name');
+
+            const steps = parsed.expression.expression.locationPath.steps;
+
+            const step0 = steps[0];
+
+            assert.strictEqual(xpath.NodeTest.NODE, step0.nodeTest.type);
+
+            const step1 = steps[1];
+
+            assert.strictEqual(xpath.NodeTest.NAMETESTPREFIXANY, step1.nodeTest.type);
+            assert.strictEqual('my', step1.nodeTest.prefix);
+
+            const step2 = steps[2];
+
+            assert.strictEqual(xpath.NodeTest.NAMETESTQNAME, step2.nodeTest.type);
+            assert.strictEqual('my', step2.nodeTest.prefix);
+            assert.strictEqual('name', step2.nodeTest.localName);
+            assert.strictEqual('my:name', step2.nodeTest.name);
+        });
+    })
+
     describe('miscellaneous', () => {
         it('should create XPathExceptions that act like Errors', () => {
             try {
diff --git a/xpath.js b/xpath.js
index 4882a27..d58a4b8 100644
--- a/xpath.js
+++ b/xpath.js
@@ -2319,12 +2319,10 @@ var xpath = (typeof exports === 'undefined') ? {} : exports;
     NodeTest.makeNodeTestType = function (type, members, ctor) {
         var newType = ctor || function () { };
 
-        newType.prototype = new NodeTest(members.type);
-        newType.prototype.constructor = type;
+        newType.prototype = new NodeTest(type);
+        newType.prototype.constructor = newType;
 
-        for (var key in members) {
-            newType.prototype[key] = members[key];
-        }
+        assign(newType.prototype, members);
 
         return newType;
     };
@@ -2364,32 +2362,40 @@ var xpath = (typeof exports === 'undefined') ? {} : exports;
             : localName === nLocalName;
     };
 
-    NodeTest.NameTestPrefixAny = NodeTest.makeNodeTestType(NodeTest.NAMETESTPREFIXANY, {
-        matches: function (n, xpc) {
-            return NodeTest.isElementOrAttribute(n) &&
-                NodeTest.nameSpaceMatches(this.prefix, xpc, n);
+    NodeTest.NameTestPrefixAny = NodeTest.makeNodeTestType(
+        NodeTest.NAMETESTPREFIXANY,
+        {
+            matches: function (n, xpc) {
+                return NodeTest.isElementOrAttribute(n) &&
+                    NodeTest.nameSpaceMatches(this.prefix, xpc, n);
+            },
+            toString: function () {
+                return this.prefix + ":*";
+            }
         },
-        toString: function () {
-            return this.prefix + ":*";
-        }
-    }, function (prefix) { this.prefix = prefix; });
+        function NameTestPrefixAny(prefix) { this.prefix = prefix; }
+    );
 
-    NodeTest.NameTestQName = NodeTest.makeNodeTestType(NodeTest.NAMETESTQNAME, {
-        matches: function (n, xpc) {
-            return NodeTest.isNodeType([1, 2, XPathNamespace.XPATH_NAMESPACE_NODE])(n) &&
-                NodeTest.nameSpaceMatches(this.prefix, xpc, n) &&
-                NodeTest.localNameMatches(this.localName, xpc, n);
+    NodeTest.NameTestQName = NodeTest.makeNodeTestType(
+        NodeTest.NAMETESTQNAME,
+        {
+            matches: function (n, xpc) {
+                return NodeTest.isNodeType([1, 2, XPathNamespace.XPATH_NAMESPACE_NODE])(n) &&
+                    NodeTest.nameSpaceMatches(this.prefix, xpc, n) &&
+                    NodeTest.localNameMatches(this.localName, xpc, n);
+            },
+            toString: function () {
+                return this.name;
+            }
         },
-        toString: function () {
-            return this.name;
-        }
-    }, function (name) {
-        var nameParts = name.split(':');
+        function NameTestQName(name) {
+            var nameParts = name.split(':');
 
-        this.name = name;
-        this.prefix = nameParts.length > 1 ? nameParts[0] : null;
-        this.localName = nameParts[nameParts.length > 1 ? 1 : 0];
-    });
+            this.name = name;
+            this.prefix = nameParts.length > 1 ? nameParts[0] : null;
+            this.localName = nameParts[nameParts.length > 1 ? 1 : 0];
+        }
+    );
 
     NodeTest.PITest = NodeTest.makeNodeTestType(NodeTest.PI, {
         matches: function (n, xpc) {