Assertables: Rust crate of assert macros for testing

The assertables Rust crate provides many assert macros to improve your compile-time tests and run-time reliability.

• Crate: https://crates.io/crates/assertables
• Docs: https://docs.rs/assertables/
• Repo: https://github.com/sixarm/assertables-rust-crate/
• Contact: joel@joelparkerhenderson.com

Introduction

The Rust programming language provides assert macros to test code:

• assert!(…)
• assert_eq!(a, b) // equal
• assert_ne!(a, b) // not equal

The assertables crate provides many more, so you can write smarter tests.

Examples:

• assert_lt!(1, 2) // compare values using less than
• assert_approx_eq!(1.0000001, 1.0000002) // compare floats
• assert_len_eq!("hello", "world") // compare lengths
• assert_starts_with!("hello world", "hello") // compare strings
• assert_fs_read_to_string_eq!("a.txt", "b.txt") // compare files

Top 3 benefits:

1. You can write better tests to improve reliability and maintainability.
2. You can handle more corner cases without needing to write custom code.
3. You can troubleshoot faster because error messages show specifics.

Top 3 features:

1. Easy to use: everything is well-documented with runnable examples.
2. Runtime savvy: all the assertables macros have runtime versions.
3. Zero overhead: if you don't use a macro, then it's never compiled.

Install

To use this crate, add it to your Cargo.toml file:

[dev-dependencies]
assertables = "8.14.0"

Highlights

For values:

• assert_lt!(a, b) // less than
• assert_le!(a, b) // less thanor equal to
• assert_gt!(a, b) // greater than
• assert_ge!(a, b) // greater thanor equal to

For approximation:

• assert_approx_eq!(a, b)
• assert_approx_ne!(a, b)

For strings:

• assert_starts_with!(a, b)
• assert_ends_with!(a, b)

For lengths:

• assert_len_eq!(a, b)
• assert_is_empty!(a)

For matching:

• assert_contains!(a, b)
• assert_is_match!(a, b)

For infix operators:

• assert_infix!(a == b)
• assert_infix!(a && b)

For nearness:

• assert_in_delta!(a, b, delta)
• assert_in_epsilon!(a, b, epsilon)

For Result Ok/Err:

• assert_ok!(a)
• assert_err!(a)

For Option Some/None:

• assert_some!(a)
• assert_none!(a)

For Poll Ready/Pending:

• assert_ready!(a)
• assert_pending!(a)

For collections such as arrays, vectors, iterators, sets:

• assert_iter_eq!(collection1, collection2)
• assert_set_eq!(collection1, collection2)

For file system paths and input/output readers:

• assert_fs_read_to_string_eq!(path1, path2)
• assert_io_read_to_string_eq!(reader1, reader2)

For command capture of standard output and standard error:

• assert_command_stdout_eq!(command1, command2)
• assert_program_args_stdout_eq!(program1, args1, program2, args2)

Modules

There are many more macros that are organized in modules.

Modules for values:

• assert_infix
• assert_approx

Modules for strings:

• assert_starts_with
• assert_ends_with

Modules for lengths:

• assert_len
• assert_is_empty

Modules for matching:

• assert_contains
• assert_is_match

Modules for collections such as arrays, vectors, iterators, sets, bags:

• assert_iter for iterator collections
• assert_set for set collections
• assert_bag for bag collections

Modules for Result Ok/Err:

• assert_ok
• assert_err

Modules for Option Some/None:

• assert_some
• assert_none

Modules for Poll Ready/Pending:

• assert_ready
• assert_pending

Modules for functions:

• assert_fn for functions in general.
• assert_fn_ok for functions that return Result::Ok.
• assert_fn_err for functions that return Result::Err.

Modules for readers:

• assert_fs_read_to_string for file system path contents.
• assert_io_read_to_string for input/output reader streams.

Modules for external calls:

• assert_command for commands with stdout/stderr.
• assert_program_args for programs with args with stdout/stderr.

Forms

All assertables macros have forms for different outcomes:

• assert_gt!(a, b) // panic during typical test
• assert_gt_as_result!(a, b) // return Ok or Err
• debug_assert_gt!(a, b) // panic when in debug mode

All assertables macros have forms for an optional message:

• assert_gt!(a, b) // automatic error message
• assert_gt!(a, b, "your text") // custom error message

Many assertables macros have forms for comparing left hand side (LHS) and right hand side (RHS) as the same type or as an expression:

• assert_ok_eq!(a, b) // Ok(…) = Ok(…)
• assert_ok_eq_expr!(a, b) // Ok(…) = expression

Tracking

• Package: assertables-rust-crate
• Version: 8.15.0
• Created: 2021-03-30T15:47:49Z
• Updated: 2024-10-06T23:11:30Z
• License: MIT or Apache-2.0 or GPL-2.0 or GPL-3.0 or contact us for more
• Contact: Joel Parker Henderson (joel@sixarm.com)