From ff9189270ef6ee5ff2f76a3ac3418d92b66e31ba Mon Sep 17 00:00:00 2001
From: Sergiu Ivanov <sivanov@colimite.fr>
Date: Sat, 16 May 2020 23:09:00 +0200
Subject: [PATCH] utils: Move the tests into the test submodule.

---
 utils-tests.rkt | 170 ----------------------------------------
 utils.rkt       | 204 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 204 insertions(+), 170 deletions(-)
 delete mode 100644 utils-tests.rkt

diff --git a/utils-tests.rkt b/utils-tests.rkt
deleted file mode 100644
index 30882ef..0000000
--- a/utils-tests.rkt
+++ /dev/null
@@ -1,170 +0,0 @@
-#lang racket
-
-;;; Tests for dds/utils.
-
-(require rackunit graph "utils.rkt")
-
-(test-case "HashTable Injection"
-  (test-case "auto-hash-ref/explicit"
-    (let ([mytable #hash((a . 3) (b . 4))])
-      (check-equal? (auto-hash-ref/explicit (mytable b a)
-                                            (* a b))
-                    12))
-    (let ([ht #hash((a . #t) (b . #f))])
-      (check-equal? (auto-hash-ref/explicit (ht a b)
-                                            (and (not a) b))
-                    #f)))
-
-  (test-case "auto-hash-ref/:"
-    (let ([ht #hash((x . #t) (y . #t) (t . #f))]
-          [z #t])
-      (check-equal? (auto-hash-ref/: ht
-                                     (and :x (not :y) z (or (and :t) :x)))
-                    #f))
-    (let ([ht #hash((a . 1) (b . 2))])
-      (check-equal? (auto-hash-ref/: ht (+ :a (* 2 :b)))
-                    5)))
-
-  (test-case "eval-with"
-    (check-equal? (let ([ht #hash((a . 1) (b . 1))])
-                    (eval-with ht '(+ b a 1)))
-                  3)))
-
-(test-case "Analysis of quoted expressions"
-  (check-equal? (extract-symbols '(1 (2 3) x (y z 3)))
-                '(x y z)))
-
-(test-case "Variable mapping and Org-mode"
-  (check-equal? (any->string 'a) "a")
-  (check-equal? (any->string '(a 1 (x y))) "(a 1 (x y))")
-  (check-equal? (any->string "hello") "hello")
-  (let ([mp (stringify-variable-mapping #hash((a . (and a b)) (b . (not b))))])
-    (check-equal? (hash-ref mp 'a) "(and a b)")
-    (check-equal? (hash-ref mp 'b) "(not b)"))
-  (check-equal? (string->any "(or b (not a))") '(or b (not a)))
-  (check-equal? (string->any "14") 14)
-  (check-equal? (map-sexp add1 '(1 2 (4 10) 3)) '(2 3 (5 11) 4))
-  (check-equal? (read-org-sexp "((\"a\" \"(and a b)\") (\"b\" \"(or b (not a))\"))")
-                '((a (and a b)) (b (or b (not a)))))
-  (check-equal? (read-org-sexp "(#t \"#t\" \"#t \" '(1 2 \"#f\"))")
-                '(#t #t #t '(1 2 #f)))
-  (check-equal? (unstringify-pairs '(("a" . "1") ("b" . "(and a (not b))")))
-                '((a . 1) (b . (and a (not b)))))
-  (check-equal? (unstringify-pairs '(("a" . 1) ("b" . "(and a (not b))")))
-                '((a . 1) (b . (and a (not b)))))
-  (let ([m1 (read-org-variable-mapping "((\"a\" \"(and a b)\") (\"b\" \"(or b (not a))\"))")]
-        [m2 (read-org-variable-mapping "((\"a\" . \"(and a b)\") (\"b\" . \"(or b (not a))\"))")]
-        [m3 (unorgv "((\"a\" . \"(and a b)\") (\"b\" . \"(or b (not a))\"))")])
-    (check-equal? (hash-ref m1 'a) '(and a b))
-    (check-equal? (hash-ref m2 'a) '(and a b))
-    (check-equal? (hash-ref m3 'a) '(and a b))
-    (check-equal? (hash-ref m1 'b) '(or b (not a)))
-    (check-equal? (hash-ref m2 'b) '(or b (not a)))
-    (check-equal? (hash-ref m3 'b) '(or b (not a))))
-  (check-equal? (read-symbol-list "a b c") '(a b c))
-  (check-equal? (drop-first-last "(a b)") "a b")
-  (check-equal? (list-sets->list-strings (list (set 'x 'y) (set 'z) (set) (set 't)))
-                '("y x" "z" "" "t"))
-  (check-equal? (pretty-print-set-sets (set (set 'a 'b) (set 'c))) "{a b}{c}"))
-
-(test-case "Additional graph utilities"
-  (let* ([gr1 (directed-graph '((a b) (b c)))]
-         [gr2 (undirected-graph '((a b) (b c)))]
-         [dbl (λ (x) (let ([x-str (symbol->string x)])
-                       (string->symbol (string-append x-str x-str))))]
-         [new-gr1 (update-vertices/unweighted gr1 dbl)]
-         [new-gr2 (update-vertices/unweighted gr2 dbl)]
-         [new-gr1-ug (update-graph gr1 #:v-func dbl)]
-         [new-gr2-ug (update-graph gr2 #:v-func dbl)]
-         [gr3 (weighted-graph/directed '((10 a b) (11 b c)))]
-         [new-gr3 (update-graph gr3 #:v-func dbl #:e-func (λ (x) (* 2 x)))])
-    (check-false (has-vertex? new-gr1 'a))
-    (check-true (has-vertex? new-gr1 'aa))
-    (check-false (has-vertex? new-gr1 'b))
-    (check-true (has-vertex? new-gr1 'bb))
-    (check-false (has-vertex? new-gr1 'c))
-    (check-true (has-vertex? new-gr1 'cc))
-    (check-true (has-edge? new-gr1 'aa 'bb))
-    (check-true (has-edge? new-gr1 'bb 'cc))
-
-    (check-true (has-edge? new-gr2 'aa 'bb))
-    (check-true (has-edge? new-gr2 'bb 'aa))
-    (check-true (has-edge? new-gr2 'bb 'cc))
-    (check-true (has-edge? new-gr2 'cc 'bb))
-
-    (check-false (has-vertex? new-gr1-ug 'a))
-    (check-true (has-vertex? new-gr1-ug 'aa))
-    (check-false (has-vertex? new-gr1-ug 'b))
-    (check-true (has-vertex? new-gr1-ug 'bb))
-    (check-false (has-vertex? new-gr1-ug 'c))
-    (check-true (has-vertex? new-gr1-ug 'cc))
-    (check-true (has-edge? new-gr1-ug 'aa 'bb))
-    (check-true (has-edge? new-gr1-ug 'bb 'cc))
-
-    (check-true (has-edge? new-gr2-ug 'aa 'bb))
-    (check-true (has-edge? new-gr2-ug 'bb 'aa))
-    (check-true (has-edge? new-gr2-ug 'bb 'cc))
-    (check-true (has-edge? new-gr2-ug 'cc 'bb))
-
-    (check-true (has-edge? new-gr3 'aa 'bb))
-    (check-false (has-edge? new-gr3 'bb 'aa))
-    (check-true (has-edge? new-gr3 'bb 'cc))
-    (check-false (has-edge? new-gr3 'cc 'bb))
-    (check-equal? (edge-weight new-gr3 'aa 'bb) 20)
-    (check-equal? (edge-weight new-gr3 'bb 'cc) 22)))
-
-(test-case "Pretty printing"
-  (check-equal? (pretty-print-set (set 'a 'b 1)) "1 a b"))
-
-(test-case "Additional list utilties"
-  (let-values ([(e1 l1) (collect-by-key '((1 2) (1 3)) '(a b))]
-               [(e2 l2) (collect-by-key '((1 2) (1 2)) '(a b))]
-               [(e3 l3) (collect-by-key/sets '(a b a) '(1 2 1))])
-    (check-equal? e1 '((1 2) (1 3))) (check-equal? l1 '((a) (b)))
-    (check-equal? e2 '((1 2))) (check-equal? l2 '((b a)))
-    (check-equal? e3 '(a b)) (check-equal? l3 (list (set 1) (set 2))))
-  (check-equal? (ht-values/list->set #hash((a . (1 1))))
-                (hash 'a (set 1)))
-  (check-equal? (hash->list/ordered #hash((b . 1) (a . 1)))
-                '((a . 1) (b . 1)))
-  (let-values ([(l1 l2) (multi-split-at '((1 2 3) (a b c)) 2)])
-    (check-equal? l1 '((1 2) (a b))) (check-equal? l2 '((3) (c))))
-  (check-equal? (lists-transpose '((1 2) (a b))) '((1 a) (2 b))))
-
-(test-case "Functions"
-  (check-true (procedure-fixed-arity? not))
-  (check-false (procedure-fixed-arity? +)))
-
-(test-case "Randomness"
-  (begin
-    (random-seed 0)
-    (check-equal? (stream->list (stream-take (in-random 100) 10))
-                  '(85 65 20 40 89 45 54 38 26 62))
-    (check-equal? (stream->list (stream-take (in-random 50 100) 10))
-                  '(75 59 82 85 61 85 59 64 75 53))
-    (check-equal? (stream->list (stream-take (in-random) 10))
-                  '(0.1656109603231493
-                    0.9680391127132195
-                    0.051518813640790355
-                    0.755901955353936
-                    0.5923534604277275
-                    0.5513340634474264
-                    0.7022057040731392
-                    0.48375400938578744
-                    0.7538961707172924
-                    0.01828428516237329))))
-
-(test-case "Additional stream utilities"
-  (check-equal? (stream->list (cartesian-product/stream (in-range 3) (in-range 4 6) '(a b)))
-                '((0 4 a)
-                  (0 4 b)
-                  (0 5 a)
-                  (0 5 b)
-                  (1 4 a)
-                  (1 4 b)
-                  (1 5 a)
-                  (1 5 b)
-                  (2 4 a)
-                  (2 4 b)
-                  (2 5 a)
-                  (2 5 b))))
diff --git a/utils.rkt b/utils.rkt
index 304fe35..4b32736 100644
--- a/utils.rkt
+++ b/utils.rkt
@@ -54,6 +54,10 @@
  ;; Syntax
  auto-hash-ref/explicit auto-hash-ref/:)
 
+(module+ test
+  (require rackunit))
+
+
 ;;; ===================
 ;;; HashTable Injection
 ;;; ===================
@@ -81,6 +85,16 @@
                 #`[#,x (hash-ref ht '#,x)])
          body)]))
 
+(module+ test
+  (let ([mytable #hash((a . 3) (b . 4))])
+    (check-equal? (auto-hash-ref/explicit (mytable b a)
+                                          (* a b))
+                  12))
+  (let ([ht #hash((a . #t) (b . #f))])
+    (check-equal? (auto-hash-ref/explicit (ht a b)
+                                          (and (not a) b))
+                  #f)))
+
 ;;; Given an expression and a (HashTable Symbol a), looks up the
 ;;; symbols with a leading semicolon and binds them to the value they
 ;;; are associated to in the hash table.
@@ -103,6 +117,16 @@
                      (hash-ref ht '#,(strip-colon x))])
            body))]))
 
+(module+ test
+  (let ([ht #hash((x . #t) (y . #t) (t . #f))]
+        [z #t])
+    (check-equal? (auto-hash-ref/: ht
+                                   (and :x (not :y) z (or (and :t) :x)))
+                  #f))
+  (let ([ht #hash((a . 1) (b . 2))])
+    (check-equal? (auto-hash-ref/: ht (+ :a (* 2 :b)))
+                  5)))
+
 ;;; The helper functions for auto-hash-ref/:.
 (begin-for-syntax
   ;; Collect all the symbols starting with a colon in datum.
@@ -148,6 +172,11 @@
     (for ([(x val) ht]) (namespace-set-variable-value! x val))
     (eval expr)))
 
+(module+ test
+  (check-equal? (let ([ht #hash((a . 1) (b . 1))])
+                  (eval-with ht '(+ b a 1)))
+                3))
+
 ;;; Same as eval-with, but returns only the first value produced by
 ;;; the evaluated expression.
 (define (eval-with1 ht expr)
@@ -169,6 +198,10 @@
                           (extract-symbols x)))]
     [else '()]))
 
+(module+ test
+  (check-equal? (extract-symbols '(1 (2 3) x (y z 3)))
+                '(x y z)))
+
 
 ;;; =========================
 ;;; Interaction with Org-mode
@@ -187,6 +220,11 @@
 (define (any->string x)
   (with-output-to-string (λ () (display x))))
 
+(module+ test
+  (check-equal? (any->string 'a) "a")
+  (check-equal? (any->string '(a 1 (x y))) "(a 1 (x y))")
+  (check-equal? (any->string "hello") "hello"))
+
 ;;; A string variable mapping is a mapping from variables to strings.
 (define (string-variable-mapping? dict) (hash/c symbol? string?))
 
@@ -194,10 +232,19 @@
 (define (stringify-variable-mapping ht)
   (for/hash ([(key val) ht]) (values key (any->string val))))
 
+(module+ test
+  (let ([mp (stringify-variable-mapping #hash((a . (and a b)) (b . (not b))))])
+    (check-equal? (hash-ref mp 'a) "(and a b)")
+    (check-equal? (hash-ref mp 'b) "(not b)")))
+
 ;;; Reads any value from string.
 (define (string->any str)
   (with-input-from-string str (λ () (read))))
 
+(module+ test
+  (check-equal? (string->any "(or b (not a))") '(or b (not a)))
+  (check-equal? (string->any "14") 14))
+
 ;;; Given a sexp, converts all "#f" to #f and "#t" to #t.
 ;;;
 ;;; When I read Org-mode tables, I pump them through a call to the
@@ -222,6 +269,9 @@
     [(? list?) (map ((curry map-sexp) func) sexp)]
     [datum (func datum)]))
 
+(module+ test
+  (check-equal? (map-sexp add1 '(1 2 (4 10) 3)) '(2 3 (5 11) 4)))
+
 ;;; Reads a sexp from a string produced by Org-mode for a named table.
 ;;; See example.org for examples.
 (define read-org-sexp
@@ -233,6 +283,12 @@
 ;;; A shortcut for read-org-sexp.
 (define unorg read-org-sexp)
 
+(module+ test
+  (check-equal? (read-org-sexp "((\"a\" \"(and a b)\") (\"b\" \"(or b (not a))\"))")
+                '((a (and a b)) (b (or b (not a)))))
+  (check-equal? (read-org-sexp "(#t \"#t\" \"#t \" '(1 2 \"#f\"))")
+                '(#t #t #t '(1 2 #f))))
+
 ;;; A contract allowing pairs constructed via cons or via list.
 (define (general-pair/c key-contract val-contract)
   (or/c (list/c key-contract val-contract)
@@ -254,11 +310,28 @@
                                       (string->any val)
                                       val))])))
 
+(module+ test
+  (check-equal? (unstringify-pairs '(("a" . "1") ("b" . "(and a (not b))")))
+                '((a . 1) (b . (and a (not b)))))
+  (check-equal? (unstringify-pairs '(("a" . 1) ("b" . "(and a (not b))")))
+                '((a . 1) (b . (and a (not b))))))
+
 ;;; Reads a variable mapping from a string, such as the one which
 ;;; Org-mode produces from tables.
 (define read-org-variable-mapping
   (compose make-immutable-hash unstringify-pairs string->any))
 
+(module+ test
+  (let ([m1 (read-org-variable-mapping "((\"a\" \"(and a b)\") (\"b\" \"(or b (not a))\"))")]
+        [m2 (read-org-variable-mapping "((\"a\" . \"(and a b)\") (\"b\" . \"(or b (not a))\"))")]
+        [m3 (unorgv "((\"a\" . \"(and a b)\") (\"b\" . \"(or b (not a))\"))")])
+    (check-equal? (hash-ref m1 'a) '(and a b))
+    (check-equal? (hash-ref m2 'a) '(and a b))
+    (check-equal? (hash-ref m3 'a) '(and a b))
+    (check-equal? (hash-ref m1 'b) '(or b (not a)))
+    (check-equal? (hash-ref m2 'b) '(or b (not a)))
+    (check-equal? (hash-ref m3 'b) '(or b (not a)))))
+
 ;;; A synonym for read-org-variable-mapping.
 (define unorgv read-org-variable-mapping)
 
@@ -269,6 +342,9 @@
 (define (read-symbol-list str)
   (string->any (string-append "(" str ")")))
 
+(module+ test
+  (check-equal? (read-symbol-list "a b c") '(a b c)))
+
 ;;; Removes the first and the last symbol of a given string.
 ;;;
 ;;; Useful for removing the parentheses in string representations of
@@ -276,11 +352,18 @@
 (define (drop-first-last str)
   (substring str 1 (- (string-length str) 1)))
 
+(module+ test
+  (check-equal? (drop-first-last "(a b)") "a b"))
+
 ;;; Converts a list of sets of symbols to a list of strings containing
 ;;; those symbols.
 (define (list-sets->list-strings lst)
   (map (compose drop-first-last any->string set->list) lst))
 
+(module+ test
+  (check-equal? (list-sets->list-strings (list (set 'x 'y) (set 'z) (set) (set 't)))
+                '("y x" "z" "" "t")))
+
 ;;; Pretty-prints a set of sets of symbols.
 ;;;
 ;;; Typically used for pretty-printing the annotations on the edges of
@@ -288,6 +371,9 @@
 (define (pretty-print-set-sets ms)
   (string-join (for/list ([m ms]) (format "{~a}" (pretty-print-set m))) ""))
 
+(module+ test
+  (check-equal? (pretty-print-set-sets (set (set 'a 'b) (set 'c))) "{a b}{c}"))
+
 
 ;;; ==========================
 ;;; Additional graph utilities
@@ -307,6 +393,27 @@
      (match-let ([(list u v) e])
        (list (func u) (func v))))))
 
+(module+ test
+  (let* ([gr1 (directed-graph '((a b) (b c)))]
+         [gr2 (undirected-graph '((a b) (b c)))]
+         [dbl (λ (x) (let ([x-str (symbol->string x)])
+                       (string->symbol (string-append x-str x-str))))]
+         [new-gr1 (update-vertices/unweighted gr1 dbl)]
+         [new-gr2 (update-vertices/unweighted gr2 dbl)])
+    (check-false (has-vertex? new-gr1 'a))
+    (check-true (has-vertex? new-gr1 'aa))
+    (check-false (has-vertex? new-gr1 'b))
+    (check-true (has-vertex? new-gr1 'bb))
+    (check-false (has-vertex? new-gr1 'c))
+    (check-true (has-vertex? new-gr1 'cc))
+    (check-true (has-edge? new-gr1 'aa 'bb))
+    (check-true (has-edge? new-gr1 'bb 'cc))
+
+    (check-true (has-edge? new-gr2 'aa 'bb))
+    (check-true (has-edge? new-gr2 'bb 'aa))
+    (check-true (has-edge? new-gr2 'bb 'cc))
+    (check-true (has-edge? new-gr2 'cc 'bb))))
+
 ;;; Given a graph, apply a transformation v-func to every vertex label
 ;;; and, if the graph is a weighted graph, the transformation e-func
 ;;; to every edge label.  Both transformations default to identity
@@ -328,6 +435,36 @@
     [else
      (weighted-graph/directed edges)]))
 
+(module+ test
+  (let* ([gr1 (directed-graph '((a b) (b c)))]
+         [gr2 (undirected-graph '((a b) (b c)))]
+         [dbl (λ (x) (let ([x-str (symbol->string x)])
+                       (string->symbol (string-append x-str x-str))))]
+         [new-gr1-ug (update-graph gr1 #:v-func dbl)]
+         [new-gr2-ug (update-graph gr2 #:v-func dbl)]
+         [gr3 (weighted-graph/directed '((10 a b) (11 b c)))]
+         [new-gr3 (update-graph gr3 #:v-func dbl #:e-func (λ (x) (* 2 x)))])
+    (check-false (has-vertex? new-gr1-ug 'a))
+    (check-true (has-vertex? new-gr1-ug 'aa))
+    (check-false (has-vertex? new-gr1-ug 'b))
+    (check-true (has-vertex? new-gr1-ug 'bb))
+    (check-false (has-vertex? new-gr1-ug 'c))
+    (check-true (has-vertex? new-gr1-ug 'cc))
+    (check-true (has-edge? new-gr1-ug 'aa 'bb))
+    (check-true (has-edge? new-gr1-ug 'bb 'cc))
+
+    (check-true (has-edge? new-gr2-ug 'aa 'bb))
+    (check-true (has-edge? new-gr2-ug 'bb 'aa))
+    (check-true (has-edge? new-gr2-ug 'bb 'cc))
+    (check-true (has-edge? new-gr2-ug 'cc 'bb))
+
+    (check-true (has-edge? new-gr3 'aa 'bb))
+    (check-false (has-edge? new-gr3 'bb 'aa))
+    (check-true (has-edge? new-gr3 'bb 'cc))
+    (check-false (has-edge? new-gr3 'cc 'bb))
+    (check-equal? (edge-weight new-gr3 'aa 'bb) 20)
+    (check-equal? (edge-weight new-gr3 'bb 'cc) 22)))
+
 
 ;;; ===============
 ;;; Pretty printing
@@ -337,6 +474,9 @@
 (define (pretty-print-set s)
   (string-join (sort (set-map s any->string) string<?)))
 
+(module+ test
+  (check-equal? (pretty-print-set (set 'a 'b 1)) "1 a b"))
+
 
 ;;; =========================
 ;;; Additional list utilities
@@ -354,20 +494,38 @@
             ([e edges] [l labels])
     (hash-update ht e (λ (ls) (cons l ls)) empty)))
 
+(module+ test
+  (let-values ([(e1 l1) (collect-by-key '((1 2) (1 3)) '(a b))]
+               [(e2 l2) (collect-by-key '((1 2) (1 2)) '(a b))])
+    (check-equal? e1 '((1 2) (1 3))) (check-equal? l1 '((a) (b)))
+    (check-equal? e2 '((1 2))) (check-equal? l2 '((b a)))))
+
 ;;; Like collect-by-key, but returns a list of sets of weights.
 (define (collect-by-key/sets edges labels)
   (let-values ([(es ls) (collect-by-key edges labels)])
     (values es (map list->set ls))))
 
+(module+ test
+  (let-values ([(e3 l3) (collect-by-key/sets '(a b a) '(1 2 1))])
+    (check-equal? e3 '(a b)) (check-equal? l3 (list (set 1) (set 2)))))
+
 ;;; Converts the values of a hash table from lists to sets.
 (define (ht-values/list->set ht)
   (for/hash ([(k v) (in-hash ht)])
     (values k (list->set v))))
 
+(module+ test
+  (check-equal? (ht-values/list->set #hash((a . (1 1))))
+                (hash 'a (set 1))))
+
 ;;; Returns the key-value pairs of a given hash table in the order in
 ;;; which the hash table orders them for hash-map and hash-for-each.
 (define (hash->list/ordered ht) (hash-map ht cons #t))
 
+(module+ test
+  (check-equal? (hash->list/ordered #hash((b . 1) (a . 1)))
+                '((a . 1) (b . 1))))
+
 ;;; Given a list of lists, splits every single list at the given
 ;;; position, and then returns two lists: one consisting of the first
 ;;; halves, and the one consisting of the second halves.
@@ -379,6 +537,10 @@
   (match (foldr split-1 (cons '() '()) lsts)
     [(cons lefts rights) (values lefts rights)]))
 
+(module+ test
+  (let-values ([(l1 l2) (multi-split-at '((1 2 3) (a b c)) 2)])
+    (check-equal? l1 '((1 2) (a b))) (check-equal? l2 '((3) (c)))))
+
 ;;; Given a list of lists of the same length, transposes them.
 ;;;
 ;;; > (lists-transpose '((1 2) (a b)))
@@ -391,6 +553,9 @@
            in-values-sequence
            ((curry apply) in-parallel)))
 
+(module+ test
+  (check-equal? (lists-transpose '((1 2) (a b))) '((1 a) (2 b))))
+
 
 ;;; =========
 ;;; Functions
@@ -402,11 +567,18 @@
   (match (procedure-arity func)
     [(arity-at-least _) #f] [arity #t]))
 
+(module+ test
+  (check-true (procedure-fixed-arity? not))
+  (check-false (procedure-fixed-arity? +)))
+
 
 ;;; ==========
 ;;; Randomness
 ;;; ==========
 
+(module+ test
+  (random-seed 0))
+
 ;;; Generates a stream of inexact random numbers.  The meaning of the
 ;;; arguments is the same as for the function random:
 ;;;
@@ -424,6 +596,23 @@
     [(k) (for/stream ([i (in-naturals)]) (random k))]
     [(min max) (for/stream ([i (in-naturals)]) (random min max))]))
 
+(module+ test
+  (check-equal? (stream->list (stream-take (in-random 100) 10))
+                '(85 65 20 40 89 45 54 38 26 62))
+  (check-equal? (stream->list (stream-take (in-random 50 100) 10))
+                '(75 59 82 85 61 85 59 64 75 53))
+  (check-equal? (stream->list (stream-take (in-random) 10))
+                '(0.1656109603231493
+                  0.9680391127132195
+                  0.051518813640790355
+                  0.755901955353936
+                  0.5923534604277275
+                  0.5513340634474264
+                  0.7022057040731392
+                  0.48375400938578744
+                  0.7538961707172924
+                  0.01828428516237329)))
+
 
 ;;; ===========================
 ;;; Additional stream utilities
@@ -443,3 +632,18 @@
   ;; 1-value stream containing the empty list, which makes all the
   ;; lists proper.
   (foldr cp-2 (sequence->stream (in-value (list))) ss))
+
+(module+ test
+  (check-equal? (stream->list (cartesian-product/stream (in-range 3) (in-range 4 6) '(a b)))
+                '((0 4 a)
+                  (0 4 b)
+                  (0 5 a)
+                  (0 5 b)
+                  (1 4 a)
+                  (1 4 b)
+                  (1 5 a)
+                  (1 5 b)
+                  (2 4 a)
+                  (2 4 b)
+                  (2 5 a)
+                  (2 5 b))))