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open! Base
(** This library provides the runtime representation of expect tests and much of the logic
for running them.
The [Test_block] module defines the runtime representation of the whole
[let%expect_test] block. It exports a [Make] functor that is used in generated code to
produce a module from the locally bound [Expect_test_config]. [run_suite] from the
resulting module takes in remaining information about the expect test, including
inline test configurations, information about the contained expectations, and a
callback containing the body of the test.
The [~expectations] argument to [run_suite] is an assoc list mapping unique ids to
[Test_node.t]s. A [Test_node.t] stores the representation of a single [[%expect]] test
AST node and collects the results of tests that reach this node.
In the body of the test, the [[%expect]] AST nodes are replaced by calls to
[run_test], with the appropriate id passed as an argument.
For an example, consider a file that contains just the simple [let%expect_test] below:
{[
let%expect_test _ =
print_string "Hello";
[%expect {| Hello |}];
print_string "world";
[%expect_exact {x|world|x}]
;;
]}
It will expand to code that looks something like this:
{[
(* This statement is added to the top of each rewritten file; it is used to make
sure tests are only run from the files in which they are declared. *)
let () =
Ppx_expect_runtime.Current_file.set
~filename_rel_to_project_root:"foo/bar/test/test.ml"
(* Each test expands into something that looks approximately like this. Some of the
arguments to [Ppx_expect_test_block.run_suite] are elided for clarity. *)
let () =
(* Prepare to read test output using the settings from [Expect_test_config] *)
let module Ppx_expect_test_block =
Ppx_expect_runtime.Make_test_block(Expect_test_config) in
Ppx_expect_test_block.run_suite
(* The name of the file in which the test is defined. This lets the runtime
check that the filename set here at ppx-time matches the one that is set by
the block above at runtime. If the test were defined in a functor and that
functor invoked from another file, the filenames would not match. *)
~filename_rel_to_project_root:"foo/bar/test/test.ml"
(* The ids that should be used when registering the trailing output test and the
uncaught exception tests. They are minted at ppx time because that is the
time that it is easiest to guarantee their uniqueness. *)
~trailing_test_id:(Ppx_expect_runtime.Expectation_id.of_int 2)
~exn_test_id:(Ppx_expect_runtime.Expectation_id.of_int 3)
(* An assoc list mapping ids to representations of expect nodes that appear in
this test. Later, when encountering expect nodes, information about them is
looked up in this table. *)
~expectations:(([(Ppx_expect_runtime.Expectation_id.of_int 1,
Ppx_expect_runtime.Test_node.Create.expect_exact
{ contents = "world"; tag = (Tag "x") }
{ start_bol = ...; start_pos = ...; end_pos = ... });
(Ppx_expect_runtime.Expectation_id.of_int 0,
Ppx_expect_runtime.Test_node.Create.expect
{ contents = " Hello "; tag = (Tag "") }
{ start_bol = ...; start_pos = ...; end_pos = ... })])
)
(* The body of the let binding is passed as a callback. *)
(fun () ->
print_string "Hello";
(* Tests are run by passing in the id of the encountered test node. *)
Ppx_expect_test_block.run_test
~test_id:(Ppx_expect_runtime.Expectation_id.of_int 0);
print_string "world";
Ppx_expect_test_block.run_test
~test_id:(Ppx_expect_runtime.Expectation_id.of_int 1))
(* This statement is added to the end of each file so that the expect test runtime
knows the file is finished executing and a new one can be set as current. *)
let () = Ppx_expect_runtime.Current_file.unset ()
]}
*)
(* Register the reachability check and corrected file writing as an evaluator with
[Ppx_inline_test_lib] *)
let () =
Ppx_inline_test_lib.add_evaluator ~f:(fun () ->
Stdlib.Sys.chdir (Lazy.force Current_file.initial_dir);
Test_node.Global_results_table.process_each_file
~f:(fun ~filename ~test_nodes ~postprocess ->
Write_corrected_file.f
test_nodes
~use_color:(Ppx_inline_test_lib.use_color ())
~in_place:(Ppx_inline_test_lib.in_place ())
~diff_command:(Ppx_inline_test_lib.diff_command ())
~diff_path_prefix:(Ppx_inline_test_lib.diff_path_prefix ())
~with_:postprocess
~filename)
|> Ppx_inline_test_lib.Test_result.combine_all)
;;
(* Alert of mid-test runtime failure. *)
let () = Stdlib.at_exit Test_block.at_exit
(* Exported definitions *)
module Expect_node_formatting = Types.Expect_node_formatting
module Compact_loc = Types.Compact_loc
module Expectation_id = Types.Expectation_id
module Delimiter = Types.String_node_format.Delimiter
module Payload = Output.Payload
module Current_file : sig
val set : filename_rel_to_project_root:string -> unit
val unset : unit -> unit
end =
Current_file
module Test_node = struct
type t = Test_node.t
module Create = Test_node.Create
module For_mlt = Test_node.For_mlt
end
module Write_corrected_file = Write_corrected_file
module Make_test_block = Test_block.Make
module For_external = Test_block.For_external
module For_apply_style = Expectation.For_apply_style
|
