Fix the processing of test filter ranges to match the documentation

CHANGES.md

@@ -21,6 +21,10 @@
 - Avoid exporting `list_tests` in the main test APIs (`Alcotest{,_lwt,_async}`).
   Use `Alcotest_engine` directly if you want this function. (#310, @CraigFe)
 
+- Fix parsing of test filter ranges to allow '-' separators (e.g. `test alpha
+  1-4`), as advertised in the manpage. The previously-used '..' separator is
+  also supported. (#312, @CraigFe)
+
 ### 1.4.0 (2021-04-15)
 
 - Add `?here` and `?pos` arguments to the test assertion functions. These can be

src/alcotest-engine/config.ml

@@ -148,7 +148,10 @@ module Key = struct
           if lower > upper then acc else range (succ lower) upper (lower :: acc)
         in
         let process_range acc s =
-          String.cuts ~sep:".." s |> List.map String.to_int |> function
+          String.cuts ~sep:".." s
+          |> List.concat_map (String.cuts ~sep:"-")
+          |> List.map String.to_int
+          |> function
           | [ Some i ] -> i :: acc
           | [ Some lower; Some upper ] when lower <= upper ->
               range lower upper acc
@@ -172,7 +175,8 @@ module Key = struct
       and+ index_cases =
         let doc =
           "A comma-separated list of test case numbers (and ranges of numbers) \
-           to run, e.g: '4,6-10,19'"
+           to run, e.g: '4,6-10,19'. When specifying ranges, both '-' and '..' \
+           are accepted as valid separators."
         in
         Arg.(
           value

src/alcotest-stdlib-ext/alcotest_stdlib_ext.ml

@@ -45,6 +45,15 @@ module List = struct
     in
     aux [] n l
 
+  let concat_map f l =
+    let rec aux f acc = function
+      | [] -> rev acc
+      | x :: l ->
+          let xs = f x in
+          (aux [@tailcall]) f (rev_append xs acc) l
+    in
+    aux f [] l
+
   let filter_map f l =
     let rec inner acc = function
       | [] -> rev acc

src/alcotest-stdlib-ext/alcotest_stdlib_ext.mli

@@ -27,6 +27,7 @@ module List : sig
   val rev_head : int -> 'a list -> 'a list
   (** Reverse a list, taking at most the first n elements of the original list. *)
 
+  val concat_map : ('a -> 'b list) -> 'a list -> 'b list
   val filter_map : ('a -> 'b option) -> 'a list -> 'b list
   val lift_result : ('a, 'b) result t -> ('a t, 'b t) result
   val init : int -> (int -> 'a) -> 'a list

test/e2e/alcotest/passing/dune.inc

@@ -11,6 +11,7 @@
    empty_test_name
    filter_name
    filter_name_regex
+   filter_range
    isatty
    json_output
    list_tests
@@ -34,6 +35,7 @@
    empty_test_name
    filter_name
    filter_name_regex
+   filter_range
    isatty
    json_output
    list_tests
@@ -255,6 +257,25 @@
  (action
    (diff filter_name_regex.expected filter_name_regex.processed)))
 
+(rule
+ (target filter_range.actual)
+ (action
+  (with-outputs-to %{target}
+   (with-accepted-exit-codes (or 0 125)
+    (run %{dep:filter_range.exe} test main 0..1,1-3,5)))))
+
+(rule
+ (target filter_range.processed)
+ (action
+  (with-outputs-to %{target}
+   (run ../../strip_randomness.exe %{dep:filter_range.actual}))))
+
+(rule
+ (alias runtest)
+ (package alcotest)
+ (action
+   (diff filter_range.expected filter_range.processed)))
+
 (rule
  (target isatty.actual)
  (action

test/e2e/alcotest/passing/filter_range.expected

@@ -0,0 +1,12 @@
+Testing `test/e2e/alcotest/passing/filter_range.ml'.
+This run has ID `<uuid>'.
+
+  [OK]          main          0   test-0.
+  [OK]          main          1   test-1.
+  [OK]          main          2   test-2.
+  [OK]          main          3   test-3.
+  [SKIP]        main          4   test-4.
+  [OK]          main          5   test-5.
+
+Full test results in `<build-context>/_build/_tests/<test-dir>'.
+Test Successful in <test-duration>s. 5 tests run.

test/e2e/alcotest/passing/filter_range.ml

@@ -0,0 +1,11 @@
+let () =
+  let should_run i =
+    (* Corresponds to ranges specified in [filter_range.opts]. *)
+    List.mem i [ 0; 1; 2; 3; 5 ]
+  in
+  let tests =
+    List.init 6 (fun i ->
+        Alcotest.test_case (Printf.sprintf "test-%d" i) `Quick (fun () ->
+            if not (should_run i) then failwith "Test should have been skipped"))
+  in
+  Alcotest.run __FILE__ [ ("main", tests) ]

test/e2e/alcotest/passing/filter_range.opts

@@ -0,0 +1 @@
+test main 0..1,1-3,5