Module Expect_test_helpers

hide_positions_in_string does line-based regexp matching to replace line numbers and column numbers that appear in source-code positions with constant text LINE and COL. This can be useful in making displayed test output less fragile.

Renders an s-expression as a string. With ~hide_positions:true, patterns in the string that match OCaml-style file positions are modified to hide the line number, column number, and character positions, to make output less fragile.

For printing an s-expression to stdout. hide_positions works as in sexp_to_string.

print_and_check_stable_type prints the bin-io digest for the given type, and the bin-io and sexp serializations of the given values. Prints an error message for any serializations that fail to round-trip, and for any bin-io serializations that exceed max_binable_length.

print_and_check_stable_int63able_type works like print_and_check_stable_type, and includes Int63.t serializations.

print_bin_ios prints the shape digest of a Binable type, and the bin-io serialization of example values. print_bin_ios is used to write expect tests that can detect if the serialization format of a stable type changes.

print_bin_ios_with_max is like print_bin_ios, except it causes a CR to be printed (using require) if any serializations are longer than the supplied max_binable_length. This is useful for ensuring that serializations fit in some required size, e.g. an ethernet MTU.

require here bool is a no-op if bool = true, but if not, prints a CR require-failed:, which will appear in the expect-test output. The CR will appear in the feature owner's fe todo, thus preventing release of the feature. require is an expect-test-friendly version of assert. It works with the normal expect-test workflow because it does not raise, and it prevents mistakenly releasing features that violate a required property. There is no need to 'X' a CR require-failed; simply fix the property tested by the require and re-run the test to restore the empty output.

require prints if_false_then_print_s only if bool = false. It is useful for including information that may help debug the problem, but that would otherwise be too voluminous. if_false_then_print_s is lazy to avoid construction of the sexp except when needed.

show_raise calls f () and prints the exception that it raises, or, if it doesn't raise, prints did not raise. show_raise ignores the result of f so that one doesn't have to put an ignore inside the body of an f that is expected to raise. ~hide_positions:true operates as in print_s, to make output less fragile.

require_does_not_raise is like show_raise, but does not print anything if the function does not raise, and prints a CR along with the exception if it does raise. Unlike for show_raise, the supplied function is required to return unit to avoid mistakes like incomplete partial application that silently would not raise, but for the wrong reason.

show_allocation calls f () and prints out the allocations, major and minor, of f. If f returns a value that should be ignored, use this idiom:

        ignore (show_allocation f : t)
      

rather than this idiom:

        show_allocation (fun () -> ignore (f () : t))
      

With the latter idiom, the compiler may optimize the computation of f () taking advantage of the fact that the result is ignored, and eliminate allocation that is intended to be measured. With the former idiom, the compiler cannot do such optimization and must compute the result of f ().

require_no_allocation f combines show_allocation with require. If f does not allocate, nothing is printed. If f allocates, a summary of the allocation is printed along with a CR comment. If f returns a value that should be ignored, you should use the idiom as described above for show_allocation.

print_and_check_container_sexps prints the sexp representation of maps, sets, hash tables, and hash sets based on the given values. For sets and hash sets, prints a CR if the sexp does not correspond to a list of elements. For maps and hash tables, prints a CR if the sexp does not correspond to an association list keyed on elements.

print_and_check_comparable_sexps is like print_and_check_container_sexps for maps and sets only.

print_and_check_hashable_sexps is like print_and_check_container_sexps for hash tables and hash sets only.