Module QCheck_base_runner

Runners for Tests

Once you have built tests using QCheck.Test.make or QCheck2.Test.make, you need to run them. This module contains several runners, which are designed to run every test and report the result.

By default, you can use run_tests in a test program as follows:

let testsuite = [
  Test.make ...;
  Test.make ...;
]

let () =
  let errcode = QCheck_base_runner.run_tests ~verbose:true testsuite in
  exit errcode

which will run the tests, and exit the program. The error code will be 0 if all tests pass, 1 otherwise.

run_tests_main can be used as a shortcut for that, also featuring command-line parsing (using Arg) to activate verbose mode and others.

State

val random_state : unit -> Stdlib.Random.State.t

Access the current random state

val verbose : unit -> bool

Is the default mode verbose or quiet?

val long_tests : unit -> bool

Is the default mode to run long tests or nor?

val set_seed : int -> unit

Change the random_state by creating a new one, initialized with the given seed.

val set_verbose : bool -> unit

Change the value of verbose ()

val set_long_tests : bool -> unit

Change the value of long_tests ()

Console message printing

In verbose mode, by default QCheck_base_runner prints frequent sub-second messages suitable for an interactive console test run. This behaviour can be changed by the environment variable QCHECK_MSG_INTERVAL. Intervals are given in seconds and can also be decimal numbers. For example, setting

QCHECK_MSG_INTERVAL=7.5

will only print a console message every 7.5 seconds. This feature can be useful in a CI context, where updates are printed on consecutive lines and one may want to avoid overflowing the CI log files with too many lines.

val get_time_between_msg : unit -> float

Get the minimum time (in seconds) to wait between printing messages.

  • since 0.9
val set_time_between_msg : float -> unit

Set the minimum time (in seconds) between messages.

  • since 0.9

Event handlers

type counter = private {
  1. start : float;
  2. expected : int;
  3. mutable gen : int;
  4. mutable passed : int;
  5. mutable failed : int;
  6. mutable errored : int;
}

The type of counter used to keep tracks of the events received for a given test cell.

type handler = {
  1. handler : 'a. 'a QCheck2.Test.handler;
}

A type to represent polymorphic-enough handlers for test cells.

type handler_gen = colors:bool -> debug_shrink:Stdlib.out_channel option -> debug_shrink_list:string list -> size:int -> out:Stdlib.out_channel -> verbose:bool -> counter -> handler

An alias type to a generator of handlers for test cells.

val default_handler : handler_gen

The default handler used.

val debug_shrinking_choices : colors:bool -> out:Stdlib.out_channel -> name:string -> 'a QCheck2.Test.cell -> step:int -> 'a -> unit

The function used by the default handler to debug shrinking choices. This can be useful to outside users trying to reproduce some of the base-runner behavior.

  • since 0.19

Run a Suite of Tests and Get Results

val run_tests : ?handler:handler_gen -> ?colors:bool -> ?verbose:bool -> ?long:bool -> ?debug_shrink:Stdlib.out_channel option -> ?debug_shrink_list:string list -> ?out:Stdlib.out_channel -> ?rand:Stdlib.Random.State.t -> QCheck2.Test.t list -> int

Run a suite of tests, and print its results. This is an heritage from the "qcheck" library.

  • returns

    an error code, 0 if all tests passed, 1 otherwise.

  • parameter colors

    if true (default), colorful output

  • parameter verbose

    if true, prints more information about test cases (default: false)

  • parameter long

    if true, runs the long versions of the tests (default: false)

  • parameter debug_shrink

    debug_shrink:(Some ch) writes a log of successful shrink attempts to channel ch, for example ~debug_shrink:(Some (open_out "mylog.txt")). Use together with a non-empty list in ~debug_shrink_list.

  • parameter debug_shrink_list

    the test names to log successful shrink attempts for, for example ~debug_shrink_list:["list_rev_is_involutive"]. Requires ~debug_shrink to be Some ch.

  • parameter out

    print output to the provided channel (default: stdout)

  • parameter rand

    start the test runner in the provided RNG state

val run_tests_main : ?argv:string array -> QCheck2.Test.t list -> 'a

Can be used as the main function of a test file. Exits with a non-0 code if the tests fail. It refers to run_tests for actually running tests after CLI options have been parsed.

The available options are:

  • "--verbose" (or "-v") for activating verbose tests
  • "--seed <n>" (or "-s <n>") for repeating a previous run by setting the random seed
  • "--long" for running the long versions of the tests

Below is an example of the output of the run_tests and run_tests_main function:

random seed: 438308050
generated  error;  fail; pass / total -     time -- test name
[✓] (1000)    0 ;    0 ; 1000 / 1000 --     0.5s -- list_rev_is_involutive
[✗] (   1)    0 ;    1 ;    0 /   10 --     0.0s -- should_fail_sort_id
[✗] (   1)    1 ;    0 ;    0 /   10 --     0.0s -- should_error_raise_exn
[✓] (1000)    0 ;    0 ; 1000 / 1000 --     0.0s -- collect_results

--- Failure --------------------------------------------------------------------

Test should_fail_sort_id failed (11 shrink steps):

[1; 0]

=== Error ======================================================================

Test should_error_raise_exn errored on (62 shrink steps):

0

exception QCheck_runner_test.Error
Raised at file "example/QCheck_runner_test.ml", line 20, characters 20-25
Called from file "src/QCheck.ml", line 839, characters 13-33


+++ Collect ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Collect results for test collect_results:

4: 207 cases
3: 190 cases
2: 219 cases
1: 196 cases
0: 188 cases

================================================================================
failure (1 tests failed, 1 tests errored, ran 4 tests)
module Color : sig ... end
module Raw : sig ... end