Struct SnapshotTest 

pub struct SnapshotTest { /* private fields */ }

Snapshot testing for rich console output.

SnapshotTest compares console output against stored snapshots. If the output differs, the test fails with a diff. When running with UPDATE_SNAPSHOTS=1, snapshots are created or updated.

Snapshot Storage

By default, snapshots are stored in tests/snapshots/ relative to the crate’s Cargo.toml. Use with_snapshot_dir to customize this location.

File Naming

• Plain text snapshots: {name}.txt
• Raw snapshots (with ANSI): {name}.raw.txt

Implementations

impl SnapshotTest

pub fn new(name: &str) -> Self

Creates a new snapshot test with the given name.

The name is used as the filename for the snapshot (with .txt extension). Snapshots are stored in tests/snapshots/ by default.

Example

let snap = SnapshotTest::new("error_display");
// Snapshot will be at tests/snapshots/error_display.txt

pub fn with_snapshot_dir(self, dir: impl AsRef<Path>) -> Self

Sets a custom snapshot directory.

Example

let snap = SnapshotTest::new("test")
    .with_snapshot_dir("/tmp/my_snapshots");

pub fn with_update_mode(self, update: bool) -> Self

Forces update mode, regardless of environment variable.

Use this for programmatic snapshot updates.

pub fn assert_snapshot(&self, console: &TestConsole)

Asserts that the console output matches the stored snapshot.

Compares the stripped output (without ANSI codes) against the snapshot.

Panics

• If the snapshot doesn’t exist and UPDATE_SNAPSHOTS is not set
• If the output doesn’t match the snapshot

Example

let console = TestConsole::new();
console.console().print("Hello, world!");

SnapshotTest::new("hello")
    .assert_snapshot(&console);

pub fn assert_snapshot_string(&self, actual: &str)

Asserts that a string matches the stored snapshot.

Panics

• If the snapshot doesn’t exist and UPDATE_SNAPSHOTS is not set
• If the string doesn’t match the snapshot

pub fn assert_raw_snapshot(&self, console: &TestConsole)

Asserts that the raw console output (with ANSI codes) matches the snapshot.

This is useful for verifying that ANSI styling is applied correctly.

Panics

• If the raw snapshot doesn’t exist and UPDATE_SNAPSHOTS is not set
• If the raw output doesn’t match the snapshot

pub fn snapshot_path(&self) -> PathBuf

Returns the path where the snapshot file would be stored.

pub fn snapshot_path_raw(&self) -> PathBuf

Returns the path where the raw snapshot file would be stored.

pub fn snapshot_exists(&self) -> bool

Checks if a snapshot exists for this test.

pub fn raw_snapshot_exists(&self) -> bool

Checks if a raw snapshot exists for this test.