Testing

A Nytrix check is an executable source file that asserts behavior and exits

non-zero on failure.

Tests are ordinary programs. That keeps examples, regressions, and integration

checks close to the language users run outside the test harness.

Minimal check

use std.core
use std.core.iter as it

def xs = [1, 2, 3, 4]
assert_eq(it.filter(xs, fn(v){ (v % 2) == 0 }), [2, 4], "even values")
assert_eq(it.reduce(xs, 0, fn(acc, v){ acc + v }), 10, "sum")

Commands

ny --color=never path/to/check.ny
ny fmt --trim --check path/to/file.ny
ny test --pattern name
ny test --with-stdlib module-or-path

.nshape checks may use flags_matrix when the same source must be compiled

through several native backends. Rows are separated by ; or escaped newlines,

and each row is appended to the normal flags for one focused harness run.

Check classes

Class	Scope
Value	Pure function, parser, encoder, or transform returns an exact value.
Boundary	File, process, socket, FFI call, or native handle crosses runtime boundaries.
Regression	A fixed bug has a small reproducer.
Integration	Multiple modules cooperate.
Visual	UI, image, font, renderer, or scene behavior changed.
Performance	Timing, allocation, throughput, or generated-code behavior changed.

Assertions

use std.core

def condition = true
def actual = [1, 2]
def expected = [1, 2]

assert(condition, "behavior name")
assert_eq(actual, expected, "behavior name")

Assertion messages name behavior, not implementation details. Exact-value

assertions define deterministic behavior. Timing assertions are performance

checks.

IO boundaries

Boundary	Deterministic setup
Files	Temporary path, exact readback, cleanup.
Processes	Bounded command, explicit stdin/stdout, timeout.
Sockets	Local server, readiness check, timeout.
HTTP	Local fixture server or documented local service requirement.
TLS	Response transport/error metadata included in assertion.
Terminal	Color disabled unless color is the behavior under test.

Code fences

Every code fence declares what it contains:

Fence	Rule
`ny`	Complete Nytrix source that must compile as an extracted doc fence.
`bash`	Shell command.
`json`	Manifest or data payload.
`text`	Grammar, output, directory tree, non-source transcript, or contextual source fragment.

Silent success is valid for runnable examples. Assertion failure, panic, nonzero

exit status, or diagnostic output carries the failure signal.

Completion

A change is complete when the focused check passes, relevant formatting/audit

commands pass, and the required build or test target passes.

For compiler, runtime, stdlib, or docs-generator changes, run

./make test --with-stdlib. For documentation-only changes, run ./make docs

and any focused checks for changed examples.