QCheck: improve int shrinker fast path

example/alcotest/output.txt.expected

@@ -11,9 +11,9 @@ Testing `my test'.
 │ [FAIL]        suite          1   fail_sort_id.                               │
 └──────────────────────────────────────────────────────────────────────────────┘
 
-test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 20 shrink steps)
+test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 17 shrink steps)
 
-[exception] test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 20 shrink steps)
+[exception] test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 17 shrink steps)
 
 
 

example/ounit/output.txt.expected

@@ -6,7 +6,7 @@ Error: tests:2:error_raise_exn (in the log).
 
 
 test `error_raise_exn` raised exception `Dune__exe__QCheck_ounit_test.Error`
-on `0 (after 63 shrink steps)`
+on `0 (after 1 shrink steps)`
 
 ------------------------------------------------------------------------------
 ==============================================================================
@@ -18,7 +18,7 @@ Error: tests:3:fail_check_err_message (in the code).
 
 
 test `fail_check_err_message` failed on ≥ 1 cases:
-0 (after 7 shrink steps)
+0 (after 1 shrink steps)
 this
 will
 always
@@ -35,7 +35,7 @@ Error: tests:1:fail_sort_id (in the log).
 Error: tests:1:fail_sort_id (in the code).
 
 
-test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 20 shrink steps)
+test `fail_sort_id` failed on ≥ 1 cases: [1; 0] (after 17 shrink steps)
 
 
 ------------------------------------------------------------------------------

example/output.txt.expected

@@ -2,13 +2,13 @@ random seed: 1234
 
 --- Failure --------------------------------------------------------------------
 
-Test should_fail_sort_id failed (18 shrink steps):
+Test should_fail_sort_id failed (15 shrink steps):
 
 [1; 0]
 
 === Error ======================================================================
 
-Test should_error_raise_exn errored on (63 shrink steps):
+Test should_error_raise_exn errored on (1 shrink steps):
 
 0
 
@@ -59,9 +59,9 @@ stats num:
 
 --- Failure --------------------------------------------------------------------
 
-Test FAIL_pred_map_commute failed (127 shrink steps):
+Test FAIL_pred_map_commute failed (128 shrink steps):
 
-([3], {_ -> 0}, {3 -> false; _ -> true})
+([0], {_ -> -1}, {0 -> false; _ -> true})
 
 --- Failure --------------------------------------------------------------------
 
@@ -71,7 +71,7 @@ Test FAIL_fun2_pred_strings failed (1 shrink steps):
 
 --- Failure --------------------------------------------------------------------
 
-Test fold_left fold_right failed (25 shrink steps):
+Test fold_left fold_right failed (23 shrink steps):
 
 (0, [1], {(1, 0) -> 1; _ -> 0})
 
@@ -84,21 +84,21 @@ l=[1], fold_left=1, fold_right=0
 
 --- Failure --------------------------------------------------------------------
 
-Test fold_left fold_right uncurried failed (111 shrink steps):
+Test fold_left fold_right uncurried failed (104 shrink steps):
 
-({(5, 7) -> 0; _ -> 7}, 0, [5; 0])
+({(7, 0) -> 1; _ -> 0}, 0, [7])
 
 --- Failure --------------------------------------------------------------------
 
-Test long_shrink failed (149 shrink steps):
+Test long_shrink failed (89 shrink steps):
 
 ([0], [-1])
 
 --- Failure --------------------------------------------------------------------
 
-Test mod3_should_fail failed (84 shrink steps):
+Test mod3_should_fail failed (1 shrink steps):
 
--21
+0
 
 +++ Stats for stats_neg ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 

src/core/QCheck.ml

@@ -471,7 +471,7 @@ module Shrink = struct
   let int x yield =
     let y = ref x in
     (* try some divisors *)
-    while !y < -2 || !y >2 do y := !y / 2; yield (x - !y); done; (* fast path *)
+    while !y < -2 || !y >2 do yield (x - !y); y := !y / 2; done; (* fast path *)
     if x>0 then yield (x-1);
     if x<0 then yield (x+1);
     ()
@@ -480,7 +480,7 @@ module Shrink = struct
     let open Int32 in
     let y = ref x in
     (* try some divisors *)
-    while !y < -2l || !y > 2l do y := div !y 2l; yield (sub x !y); done; (* fast path *)
+    while !y < -2l || !y > 2l do yield (sub x !y); y := div !y 2l; done; (* fast path *)
     if x>0l then yield (pred x);
     if x<0l then yield (succ x);
     ()
@@ -489,7 +489,7 @@ module Shrink = struct
     let open Int64 in
     let y = ref x in
     (* try some divisors *)
-    while !y < -2L || !y > 2L do y := div !y 2L; yield (sub x !y); done; (* fast path *)
+    while !y < -2L || !y > 2L do yield (sub x !y); y := div !y 2L; done; (* fast path *)
     if x>0L then yield (pred x);
     if x<0L then yield (succ x);
     ()

test/core/qcheck2_output.txt.expected → test/core/QCheck2_expect_test.expected

@@ -1,168 +1,4 @@
 random seed: 1234
-2724675603984413065
-0
-1362337801992206532
-0
-681168900996103266
-0
-340584450498051633
-0
-170292225249025816
-0
-85146112624512908
-0
-42573056312256454
-0
-21286528156128227
-0
-10643264078064113
-0
-5321632039032056
-0
-2660816019516028
-0
-1330408009758014
-0
-665204004879007
-0
-332602002439503
-0
-166301001219751
-0
-83150500609875
-0
-41575250304937
-0
-20787625152468
-0
-10393812576234
-0
-5196906288117
-0
-2598453144058
-0
-1299226572029
-0
-649613286014
-0
-324806643007
-0
-162403321503
-0
-81201660751
-0
-40600830375
-0
-20300415187
-0
-10150207593
-0
-5075103796
-0
-2537551898
-0
-1268775949
-0
-634387974
-0
-317193987
-0
-158596993
-0
-79298496
-0
-39649248
-0
-19824624
-0
-9912312
-0
-4956156
-0
-2478078
-0
-1239039
-0
-619519
-0
-309759
-0
-154879
-0
-77439
-0
-38719
-0
-19359
-0
-9679
-0
-4839
-0
-2419
-0
-1209
-0
-604
-0
-302
-0
-151
-0
-75
-0
-37
-0
-18
-0
-9
-0
-4
-0
-2
-0
-1
-0
-[7; 1; 42; 1; 8; 5; 3; 9; 5; 38; 3; 3; 0; 1; 98; 1; 4; 13; 9; 2; 6; 9; 47; 6; 5; 8; 8; 6; 0; 9; 7; 2; 8; 6; 62; 6; 4; 31; 19; 1; 41; 60; 6; 5; 8; 1; 1; 4; 7; 7; 0; 5; 5; 71; 14; 26; 47; 5; 1; 6; 34; 9; 4; 2; 37; 3; 8; 4; 31; 6; 2; 1; 0; 7; 5; 1; 0; 15; 6; 1; 8; 13; 0; 6; 2; 4; 2; 6; 6; 1; 4; 1; 9; 79; 0; 87; 6; 8; 8; 62; 1; 4; 62; 6; 31; 1; 5; 6; 5; 9; 3; 3; 1; 79; 4; 3; 2; 67; 5; 7; 12; 70; 8; 8; 6; 1; 3; 14; 15; 1; 61; 4; 1; 4; 1; 7; 4; 4; 4; 2; 8; 8; 7; 5; 4; 27; 0; 9; 80; 25; 1; 8; 1; 3; 7; 4; 3; 5; 5; 6; 5; 5; 31; 7; 0; 3; 3; 6; 71; 76; 28; 60; 6; 2; 6; 3; 0; 4; 1; 0; 5; 7; 0; 28; 86; 4; 7; 51; 36; 0; 5; 0; 1; 4; 3; 6; 0; 1; 1; 8; 18; 4; 2; 8; 8; 1; 4; 7; 1; 0; 93; 5; 3; 0; 80; 1; 7; 7; 8; 8; 5; 7; 8; 9; 24; 4; 25; 8; 8; 5; 4; 90; 4; 6; 8; 4; 4; 0; 60; 8; 9; 7; 44; 5; 1; 2; 9; 74; 7; 7]
-[]
-[9; 61; 8; 4; 69; 2; 0; 72; 4; 41; 3; 8; 75; 83; 7; 7; 3; 9; 5; 8; 4; 1; 0; 2; 1; 4; 7; 6; 2; 1; 4; 86; 3; 79; 7; 86; 52; 39; 19; 0; 4; 7; 7; 7; 0; 4; 8; 8; 0; 5; 13; 1; 5; 0; 7; 12; 64; 34; 1; 1; 85; 8; 2; 9; 76; 0; 2; 5; 76; 69; 8; 8; 0; 1; 2; 2; 4; 60; 29; 5; 9; 4; 0; 8; 3; 3; 5; 1; 35; 8; 2; 7; 23; 61; 56; 8; 1; 1; 78; 7; 5; 0; 30; 9; 3; 7; 28; 57; 98; 3; 52; 3; 82; 7; 5; 5; 6; 8; 1; 6; 8; 9; 8; 16; 0]
-[]
-[1; 9; 8; 28; 47; 8; 5; 6; 8; 9; 2; 5; 8; 30; 6; 8; 84; 0; 6; 7; 76; 7; 9; 1; 0; 5; 76; 95; 2; 2; 1; 45; 7; 8; 8; 1; 6; 37; 5; 6; 73; 8; 0; 85; 8; 0; 4; 5; 2; 0; 26; 59; 0; 5; 13; 4; 7; 3; 6; 8; 1; 3]
-[]
-[5; 0; 0; 4; 10; 2; 4; 9; 5; 73; 6; 1; 5; 5; 3; 10; 5; 31; 1; 4; 3; 8; 9; 13; 41; 20; 96; 5; 1; 2; 8]
-[]
-[9; 8; 73; 5; 8; 2; 1; 8; 2; 6; 4; 18; 5; 76; 3]
-[]
-[0; 6; 2; 8; 8; 1; 4]
-[]
-[5; 2; 3]
-[]
-[3]
-[]
-[0]
-[7; 1; 42; 1; 8; 5; 3; 9; 5; 38; 3; 3; 0; 1; 98; 1; 4; 13; 9; 2; 6; 9; 47; 6; 5; 8; 8; 6; 0; 9; 7; 2; 8; 6; 62; 6; 4; 31; 19; 1; 41; 60; 6; 5; 8; 1; 1; 4; 7; 7; 0; 5; 5; 71; 14; 26; 47; 5; 1; 6; 34; 9; 4; 2; 37; 3; 8; 4; 31; 6; 2; 1; 0; 7; 5; 1; 0; 15; 6; 1; 8; 13; 0; 6; 2; 4; 2; 6; 6; 1; 4; 1; 9; 79; 0; 87; 6; 8; 8; 62; 1; 4; 62; 6; 31; 1; 5; 6; 5; 9; 3; 3; 1; 79; 4; 3; 2; 67; 5; 7; 12; 70; 8; 8; 6; 1; 3; 14; 15; 1; 61; 4; 1; 4; 1; 7; 4; 4; 4; 2; 8; 8; 7; 5; 4; 27; 0; 9; 80; 25; 1; 8; 1; 3; 7; 4; 3; 5; 5; 6; 5; 5; 31; 7; 0; 3; 3; 6; 71; 76; 28; 60; 6; 2; 6; 3; 0; 4; 1; 0; 5; 7; 0; 28; 86; 4; 7; 51; 36; 0; 5; 0; 1; 4; 3; 6; 0; 1; 1; 8; 18; 4; 2; 8; 8; 1; 4; 7; 1; 0; 93; 5; 3; 0; 80; 1; 7; 7; 8; 8; 5; 7; 8; 9; 24; 4; 25; 8; 8; 5; 4; 90; 4; 6; 8; 4; 4; 0; 60; 8; 9; 7; 44; 5; 1; 2; 9; 74; 7; 7]
-[]
-[9; 61; 8; 4; 69; 2; 0; 72; 4; 41; 3; 8; 75; 83; 7; 7; 3; 9; 5; 8; 4; 1; 0; 2; 1; 4; 7; 6; 2; 1; 4; 86; 3; 79; 7; 86; 52; 39; 19; 0; 4; 7; 7; 7; 0; 4; 8; 8; 0; 5; 13; 1; 5; 0; 7; 12; 64; 34; 1; 1; 85; 8; 2; 9; 76; 0; 2; 5; 76; 69; 8; 8; 0; 1; 2; 2; 4; 60; 29; 5; 9; 4; 0; 8; 3; 3; 5; 1; 35; 8; 2; 7; 23; 61; 56; 8; 1; 1; 78; 7; 5; 0; 30; 9; 3; 7; 28; 57; 98; 3; 52; 3; 82; 7; 5; 5; 6; 8; 1; 6; 8; 9; 8; 16; 0]
-[]
-[1; 9; 8; 28; 47; 8; 5; 6; 8; 9; 2; 5; 8; 30; 6; 8; 84; 0; 6; 7; 76; 7; 9; 1; 0; 5; 76; 95; 2; 2; 1; 45; 7; 8; 8; 1; 6; 37; 5; 6; 73; 8; 0; 85; 8; 0; 4; 5; 2; 0; 26; 59; 0; 5; 13; 4; 7; 3; 6; 8; 1; 3]
-[]
-[5; 0; 0; 4; 10; 2; 4; 9; 5; 73; 6; 1; 5; 5; 3; 10; 5; 31; 1; 4; 3; 8; 9; 13; 41; 20; 96; 5; 1; 2; 8]
-[]
-[9; 8; 73; 5; 8; 2; 1; 8; 2; 6; 4; 18; 5; 76; 3]
-[]
-[0; 6; 2; 8; 8; 1; 4]
-[]
-[5; 2; 3]
-[3; 2; 7; 3; 3]
-[]
-[5; 3]
-[5; 3; 2]
-[9; 87; 7; 0]
-[0; 2; 7; 3; 3]
-[0; 0; 7; 3; 3]
-[0; 0; 0; 3; 3]
-[0; 0; 0; 0; 3]
-[0; 0; 0; 0; 0]
 
 --- Failure --------------------------------------------------------------------
 

test/core/QCheck2_expect_test.ml

@@ -165,7 +165,7 @@ module Shrink = struct
 
   let ints_are_0 =
     Test.make ~name:"ints are 0" ~count:1000 ~print:Print.int
-      Gen.int (fun i -> Printf.printf "%i\n" i; i = 0)
+      Gen.int (fun i -> i = 0)
 
   (* test from issue #59 *)
   let ints_smaller_209609 =
@@ -195,11 +195,9 @@ module Shrink = struct
       (fun s -> String.to_seq s |> Seq.fold_left (fun acc c -> acc && c <> '\255') true)
 
   (* tests from issue #64 *)
-  let print_list xs = print_endline Print.(list int xs)
-
   let lists_are_empty_issue_64 =
     Test.make ~name:"lists are empty" ~print:Print.(list int)
-      Gen.(list small_int) (fun xs -> print_list xs; xs = [])
+      Gen.(list small_int) (fun xs -> xs = [])
 
   let list_shorter_10 =
     Test.make ~name:"lists shorter than 10" ~print:Print.(list int)
@@ -230,7 +228,7 @@ module Shrink = struct
     Test.make ~name:"lists have unique elems" ~print:Print.(list int)
       Gen.(list small_int)
       (fun xs -> let ys = List.sort_uniq Int.compare xs in
-                 print_list xs; List.length xs = List.length ys)
+                 List.length xs = List.length ys)
 
   let tree_contains_only_42 =
     Test.make ~name:"tree contains only 42" ~print:IntTree.print_tree