Crate datatest_stable

datatest-stable is a test harness intended to write file-driven or data-driven tests, where individual test cases are specified as files and not as code.

Given:

• a test my_test that accepts a path, and optionally the contents as input
• a directory to look for files in
• a pattern to match files on

datatest-stable will call the my_test function once per matching file in the directory.

datatest-stable works with cargo nextest, and is part of the nextest-rs organization on GitHub.

Usage

1. Configure the test target by setting harness = false in Cargo.toml:

[[test]]
name = "<test target name>"
harness = false

2. Call the datatest_stable::harness!(testfn, root, pattern) macro with the following parameters:

• testfn - The test function to be executed on each matching input. This function can be one of:
  • fn(&Path) -> datatest_stable::Result<()>
  • fn(&Utf8Path) -> datatest_stable::Result<()> (Utf8Path is part of the camino library, and is re-exported here for convenience.)
  • fn(&P, String) -> datatest_stable::Result<()> where P is Path or Utf8Path. If the extra String parameter is specified, the contents of the file will be loaded and passed in as a string (erroring out if that failed).
  • fn(&P, Vec<u8>) -> datatest_stable::Result<()> where P is Path or Utf8Path. If the extra Vec<u8> parameter is specified, the contents of the file will be loaded and passed in as a Vec<u8> (erroring out if that failed).
• root - The path to the root directory where the input files (fixtures) live. This path is relative to the root of the crate (the directory where the crate’s Cargo.toml is located).
• pattern - a regex used to match against and select each file to be tested. Extended regexes with lookaround and backtracking are supported via the fancy_regex crate.

The three parameters can be repeated if you have multiple sets of data-driven tests to be run: datatest_stable::harness!(testfn1, root1, pattern1, testfn2, root2, pattern2).

Examples

This is an example test. Use it with harness = false.

use datatest_stable::Utf8Path;
use std::path::Path;

fn my_test(path: &Path) -> datatest_stable::Result<()> {
    // ... write test here

    Ok(())
}

fn my_test_utf8(path: &Utf8Path, contents: String) -> datatest_stable::Result<()> {
    // ... write test here

    Ok(())
}

datatest_stable::harness!(
    my_test, "path/to/fixtures", r"^.*/*",
    my_test_utf8, "path/to/fixtures", r"^.*/*",
);

Minimum supported Rust version (MSRV)

The minimum supported Rust version is Rust 1.72. MSRV bumps may be accompanied by a minor version update; at any time, Rust versions from at least the last 6 months are supported.

See also

• datatest: the original inspiration for this crate, with more features but targeting nightly Rust.
• Data-driven testing

Re-exports

• pub use camino::Utf8Path;

Macros

• harness
  datatest-stable test harness entry point. Should be declared in the test module.

Type Aliases

• Result
  The result type for datatest-stable tests.