cmux Testing

Test framework

Swift Testing is the current Apple-supported primitive for tests on this codebase (shipped with Swift 6 / Xcode 16, supported on the macOS versions we target). Use it for everything that is not a UI test.

Default to Swift Testing for all unit and integration tests.
```
import Testing
```
, annotate tests with
```
@Test
```
, group with
```
@Suite
```
, assert with
```
#expect(...)
```
and
```
try #require(...)
```
. Do not write new tests with
```
import XCTest
```
unless they are UI tests.
UI tests stay on XCTest / XCUITest. Swift Testing does not support UI testing (no
```
XCUIApplication
```
integration). Files under
```
cmuxUITests/
```
continue to use
```
XCTestCase
```
+
```
XCUIApplication
```
. Do not migrate them and do not try to bridge Swift Testing into UI tests.
New test targets start on Swift Testing. Every new Swift package's
```
Tests/<Name>Tests/
```
directory (e.g.
```
Packages/CmuxSettings/Tests/CmuxSettingsTests/
```
) should ship with Swift Testing from the first commit. Xcode 16 auto-detects the framework based on the
```
import Testing
```
statement; no extra
```
Package.swift
```
configuration is required.
Migration guide when touching an existing XCTest test. Convert in place:
```
XCTestCase
```
subclass becomes a
```
@Suite struct
```
(or
```
final class
```
if you need a reference type); each
```
func testFoo()
```
becomes
```
@Test func foo()
```
;
```
XCTAssertEqual(a, b)
```
becomes
```
#expect(a == b)
```
;
```
XCTAssertTrue(cond)
```
becomes
```
#expect(cond)
```
;
```
XCTUnwrap(x)
```
becomes
```
try #require(x)
```
;
```
XCTFail("msg")
```
becomes
```
Issue.record("msg")
```
.
```
setUp()
```
becomes
```
init()
```
on the suite;
```
tearDown()
```
becomes
```
deinit
```
. Async setup is
```
async init()
```
. Do not bulk-rewrite untouched tests; migrate incrementally as a side effect of editing the file.
Parameterized tests use
```
@Test(arguments: [...])
```
. Prefer this over duplicate test methods.
Parallelization and shared state. Swift Testing runs tests in parallel by default, including across suites. If a suite genuinely needs ordering or guards shared mutable state, annotate it with
```
.serialized
```
instead of adding locks or sleeps.
Tags with
```
@Test(.tags(.something))
```
(or on a
```
@Suite
```
) let CI and local runs filter selectively.

Test target validation

reload.sh

does not compile the test target. It builds only the

cmux

scheme, so a green

reload.sh

says nothing about whether

cmuxTests

cmuxUITests

still compile. A symbol that is moved or renamed can keep the

cmux

app building while breaking the test target (real case: a

write(to:atomically:)

typo and a removed

TabManager.CommandResult

only surfaced in the

tests

job). Before pushing package/refactor changes, build the

cmux-unit

scheme (with

-derivedDataPath /tmp/cmux-<tag>

and, for

cmuxApp

AppDelegate

churn, the GlobalISel workaround flag) or let the

tests

CI job gate it — never treat

reload.sh

alone as proof the tests build.

cmux-testing

NPX Install

Tags

SKILL.md Content

cmux Testing

Test framework

Test target validation