diff --git a/collects/tests/mzscheme/trait.ss b/collects/tests/mzscheme/trait.ss
new file mode 100644
index 0000000000..0241fa46ac
--- /dev/null
+++ b/collects/tests/mzscheme/trait.ss
@@ -0,0 +1,149 @@
+
+(load-relative "loadtest.ss")
+
+(require (lib "class.ss")
+         (lib "trait.ss"))
+
+(Section 'trait)
+
+;; ----------------------------------------
+;; fields
+
+(test 'yes 't
+      (send (new ((trait->mixin (trait
+                                 (field [ok? 'yes])
+                                 (define/public (check) ok?)))
+                  object%))
+            check))
+
+(test 'no 't
+      (send (new ((trait->mixin 
+                   (trait-sum
+                    (trait-exclude-field (trait
+                                          (field [ok? 'yes])
+                                          (define/public (check) ok?))
+                                         ok?)
+                    (trait (field [ok? 'no]))))
+                  object%))
+            check))
+
+(err/rt-test (trait-sum
+              (trait (field [x 'x]))
+              (trait (field [x 'y]))))
+
+;; ----------------------------------------
+;; internal and external names
+
+(test 'hi 't
+      (send (new ((trait->mixin (trait
+                                 (public hello)
+                                 (define (hello) 'hi)))
+                  object%))
+            hello))
+
+(test 'hi 't
+      (send (new ((trait->mixin 
+                   (trait
+                    (public [nihao hello])
+                    (define (nihao) 'hi)))
+                  object%))
+            hello))
+
+(test 'hey 't
+      (send (new ((trait->mixin 
+                   (trait-sum
+                    (trait
+                     (public [nihao howdy])
+                     (define (nihao) 'hey))
+                    (trait
+                     (public hello)
+                     (inherit [hola howdy])
+                     (define (hello) (hola)))))
+                  object%))
+            hello))
+
+;; ----------------------------------------
+
+(test '(zoo (100))
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (y) (list (inner #t y)))))
+                         (class object% 
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (super-new)))
+                   (define/augment (y) 100)
+                   (super-new)))
+            y))
+
+(test '(too (200))
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (y) (list (inner #t y)))
+                                              (define/augment (x) (list (inner #f x)))))
+                         (class object% 
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (define/pubment (x) (list 'too (inner #f x)))
+                           (super-new)))
+                   (define/augment (y) 100)
+                   (define/augment (x) 200)
+                   (super-new)))
+            x))
+
+(test '(8 (12 (#t))) ; OR '(8 (12 100)) !!!!!!!!!!!!!!!
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (x) (list 12 (inner #f y)))
+                                              (define/augment (y) (list (inner #t x)))))
+                         (class object% 
+                           (define/pubment (x) (list 8 (inner 90 x)))
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (super-new)))
+                   (define/augment (y) 100)
+                   (super-new)))
+            x))
+
+(test '(8 (12 (#t))) ;; OR '(8 (12 #f)) !!!!!!!!!!!!!!!!!!!!!!!!!
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (x) (list 12 (inner #f y)))
+                                              (define/augment (y) (list (inner #t x)))))
+                         (class object% 
+                           (define/pubment (x) (list 8 (inner 90 x)))
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (super-new)))
+                   (super-new)))
+            x))
+
+(test '(zoo (#t))
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (x) (list 12 (inner #f y)))
+                                              (define/augment (y) (list (inner #t x)))))
+                         (class object% 
+                           (define/pubment (x) (list 8 (inner 90 x)))
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (super-new)))
+                   (define/augment (y) 100)
+                   (super-new)))
+            y))
+
+(test '(zoo (100))
+      't
+      (send (new (class ((trait->mixin (trait (define/augment (x) (list 12 (inner #f y)))
+                                              (define/augment (y) (list (inner #t x)))))
+                         (class object% 
+                           (define/pubment (x) (list 8 (inner 90 x)))
+                           (define/pubment (y) (list 'zoo (inner #f y)))
+                           (super-new)))
+                   (define/augment (x) 100)
+                   (super-new)))
+            y))
+
+(test '(12 100)
+      't
+      (send (new (class ((trait->mixin (trait (define/overment (x) (list 12 (inner #f x)))))
+                         (class object% 
+                           (define/public (x) 'zoo)
+                           (super-new)))
+                   (define/augment (x) 100)
+                   (super-new)))
+            x))
+
+;;----------------------------------------
+
+(report-errs)