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//! <div align="center"> //! <img src="https://github.com/mitsuhiko/insta/blob/master/assets/logo.png?raw=true" width="250" height="250"> //! <p><strong>insta: a snapshot testing library for Rust</strong></p> //! </div> //! //! # How it Operates //! //! This crate exports multiple macros for snapshot testing: //! //! - `assert_snapshot_matches!` for comparing basic string snapshots. //! - `assert_debug_snapshot_matches!` for comparing `Debug` outputs of values. //! - `assert_yaml_snapshot_matches!` for comparing YAML serialized //! output of types implementing `serde::Serialize`. //! - `assert_ron_snapshot_matches!` for comparing RON serialized output of //! types implementing `serde::Serialize`. //! - `assert_json_snapshot_matches!` for comparing JSON serialized output of //! types implementing `serde::Serialize`. //! //! Snapshots are stored in the `snapshots` folder right next to the test file //! where this is used. The name of the file is `<module>__<name>.snap` where //! the `name` of the snapshot has to be provided to the assertion macro. //! //! Additionally snapshots can also be stored inline. In that case the //! `cargo-insta` tool is necessary. See [inline snapshots](#inline-snapshots) //! for more information. //! //! For macros that work with `serde::Serialize` this crate also permits //! redacting of partial values. See [redactions](#redactions) for more //! information. //! //! <img src="https://github.com/mitsuhiko/insta/blob/artwork/screencast.gif?raw=true" alt=""> //! //! # Example //! //! Install `insta` and `cargo-insta`: //! //! ```ignore //! $ cargo add --dev insta //! $ cargo install cargo-insta //! ``` //! //! ```rust,ignore //! use insta::assert_debug_snapshot_matches; //! //! #[test] //! fn test_snapshots() { //! let value = vec![1, 2, 3]; //! assert_debug_snapshot_matches!("snapshot_name", value); //! } //! ``` //! //! The recommended flow is to run the tests once, have them fail and check //! if the result is okay. By default the new snapshots are stored next //! to the old ones with the extra `.new` extension. Once you are satisifed //! move the new files over. You can also use `cargo insta review` which //! will let you interactively review them: //! //! ```ignore //! $ cargo test //! $ cargo insta review //! ``` //! //! For more information on updating see [Snapshot Updating]. //! //! [Snapshot Updating]: #snapshot-updating //! //! # Snapshot files //! //! The committed snapshot files will have a header with some meta information //! that can make debugging easier and the snapshot: //! //! ```ignore //! --- //! created: "2019-01-21T22:03:13.792906+00:00" //! creator: insta@0.3.0 //! expression: "&User{id: Uuid::new_v4(), username: \"john_doe\".to_string(),}" //! source: tests/test_redaction.rs //! --- //! [ //! 1, //! 2, //! 3 //! ] //! ``` //! //! # Snapshot Updating //! //! During test runs snapshots will be updated according to the `INSTA_UPDATE` //! environment variable. The default is `auto` which will write all new //! snapshots into `.snap.new` files if no CI is detected. //! //! `INSTA_UPDATE` modes: //! //! - `auto`: the default. `no` for CI environments or `new` otherwise //! - `always`: overwrites old snapshot files with new ones unasked //! - `new`: write new snapshots into `.snap.new` files. //! - `no`: does not update snapshot files at all (just runs tests) //! //! When `new` is used as mode the `cargo-insta` command can be used to review //! the snapshots conveniently: //! //! ```ignore //! $ cargo install cargo-insta //! $ cargo test //! $ cargo insta review //! ``` //! //! "enter" or "a" accepts a new snapshot, "escape" or "r" rejects, //! "space" or "s" skips the snapshot for now. //! //! For more information invoke `cargo insta --help`. //! //! # Test Assertions //! //! By default the tests will fail when the snapshot assertion fails. However //! if a test produces more than one snapshot it can be useful to force a test //! to pass so that all new snapshots are created in one go. //! //! This can be enabled by setting `INSTA_FORCE_PASS` to `1`: //! //! ```ignore //! $ INSTA_FORCE_PASS=1 cargo test --no-fail-fast //! ``` //! //! A better way to do this is to run `cargo insta test --review` which will //! run all tests with force pass and then bring up the review tool: //! //! ```ignore //! $ cargo insta test --review //! ``` //! //! # Redactions //! //! For all snapshots created based on `serde::Serialize` output `insta` //! supports redactions. This permits replacing values with hardcoded other //! values to make snapshots stable when otherwise random or otherwise changing //! values are involved. //! //! Redactions can be defined as the third argument to those macros with //! the syntax `{ selector => replacement_value }`. //! //! The following selectors exist: //! //! - `.key`: selects the given key //! - `["key"]`: alternative syntax for keys //! - `[index]`: selects the given index in an array //! - `[]`: selects all items on an array //! - `[:end]`: selects all items up to `end` (excluding, supports negative indexing) //! - `[start:]`: selects all items starting with `start` //! - `[start:end]`: selects all items from `start` to `end` (end excluding, //! supports negative indexing). //! - `.*`: selects all keys on that depth //! //! Example usage: //! //! ```rust,ignore //! #[derive(Serialize)] //! pub struct User { //! id: Uuid, //! username: String, //! extra: HashMap<String, String>, //! } //! //! assert_yaml_snapshot_matches!("user", &User { //! id: Uuid::new_v4(), //! username: "john_doe".to_string(), //! extra: { //! let mut map = HashMap::new(); //! map.insert("ssn".to_string(), "123-123-123".to_string()); //! map //! }, //! }, { //! ".id" => "[uuid]", //! ".extra.ssn" => "[ssn]" //! }); //! ``` //! //! # Inline Snapshots //! //! Additionally snapshots can also be stored inline. In that case the format //! for the snapshot macros is `assert_snapshot_matches!(reference_value, @"snapshot")`. //! The leading at sign (`@`) indicates that the following string is the //! reference value. `cargo-insta` will then update that string with the new //! value on review. //! //! Example: //! //! ```rust,ignore //! #[derive(Serialize)] //! pub struct User { //! username: String, //! } //! //! assert_yaml_snapshot_matches!(User { //! username: "john_doe".to_string(), //! }, @""); //! ``` //! //! After the initial test failure you can run `cargo insta review` to //! accept the change. The file will then be updated automatically. #[macro_use] mod macros; mod content; mod redaction; mod runtime; mod serialization; mod snapshot; #[cfg(test)] mod test; pub use crate::snapshot::{MetaData, Snapshot}; // exported for cargo-insta only #[doc(hidden)] pub use crate::{runtime::print_snapshot_diff, snapshot::PendingInlineSnapshot}; // these are here to make the macros work #[doc(hidden)] pub mod _macro_support { pub use crate::content::Content; pub use crate::redaction::Selector; pub use crate::runtime::{assert_snapshot, ReferenceValue}; pub use crate::serialization::{ serialize_value, serialize_value_redacted, SerializationFormat, }; }