Fix data-race when running sub-tests in goroutines

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project are documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Fixed
+
+- Fixed a data-race when running sub-tests in separate goroutines.
+
 ## [1.3.1] - 2026-05-29
 
 ### Added

internal/syncutil/syncutil.go

@@ -0,0 +1,29 @@
+package syncutil
+
+import "sync"
+
+// Guarded wraps given type in a [sync.RWMutex].
+type Guarded[T any] struct {
+	value T
+	mu    sync.RWMutex
+}
+
+func (g *Guarded[T]) Load() T {
+	g.mu.RLock()
+	defer g.mu.RUnlock()
+
+	return g.value
+}
+
+func (g *Guarded[T]) Store(value T) {
+	g.Modify(func(v *T) {
+		*v = value
+	})
+}
+
+func (g *Guarded[T]) Modify(f func(value *T)) {
+	g.mu.Lock()
+	defer g.mu.Unlock()
+
+	f(&g.value)
+}

runner.go

@@ -141,7 +141,9 @@ func RunSubSuite[Suite suite[Sub], Parent, Sub CommonT](
 
 	r := newRunner[Suite](t)
 
-	return r.runSuite(t.unwrap().testingT, suite, &t.unwrap().reflection.Suite, options...)
+	parent := t.unwrap().reflection.Load().Suite
+
+	return r.runSuite(t.unwrap().testingT, suite, &parent, options...)
 }
 
 // Run runs f as a subtest of t called name. It runs f in a separate goroutine
@@ -174,14 +176,19 @@ func Run[T CommonT](
 			&parentT,
 			func(t *testoT) {
 				t.testNamer = parentT.unwrap().testNamer
-				t.reflection.Suite = parentT.unwrap().reflection.Suite
-				t.reflection.Test = testoreflect.RegularTestInfo{
-					Name:        parentT.unwrap().testNamer.Name(parentT.unwrap().Name(), name),
-					RawBaseName: name,
-					Level:       t.level(),
-					IsSubtest:   true,
-					FuncPC:      reflect.ValueOf(f).Pointer(),
-				}
+
+				parentSuite := parentT.unwrap().reflection.Load().Suite
+
+				t.reflection.Modify(func(r *testoreflect.Reflection) {
+					r.Suite = parentSuite
+					r.Test = testoreflect.RegularTestInfo{
+						Name:        parentT.unwrap().testNamer.Name(parentT.unwrap().Name(), name),
+						RawBaseName: name,
+						Level:       t.level(),
+						IsSubtest:   true,
+						FuncPC:      reflect.ValueOf(f).Pointer(),
+					}
+				})
 			},
 			options...,
 		)
@@ -190,10 +197,12 @@ func Run[T CommonT](
 			if r := recover(); r != nil {
 				trace := string(debug.Stack())
 
-				t.unwrap().reflection.Panic = &testoreflect.PanicInfo{
-					Value: r,
-					Trace: trace,
-				}
+				t.unwrap().reflection.Modify(func(r *testoreflect.Reflection) {
+					r.Panic = &testoreflect.PanicInfo{
+						Value: r,
+						Trace: trace,
+					}
+				})
 
 				t.Fatalf("testo: test %q panicked: %v\n\n%s", t.Name(), r, trace)
 			}
@@ -269,11 +278,14 @@ func (r *runner[Suite, T]) runSuite(
 			nil,
 			func(t *testoT) {
 				t.testNamer = r.testNamer
-				t.reflection.Suite = suiteInfo
-				t.reflection.Test = testoreflect.RegularTestInfo{
-					Name:        r.caller,
-					RawBaseName: r.suiteName,
-				}
+
+				t.reflection.Modify(func(ref *testoreflect.Reflection) {
+					ref.Suite = suiteInfo
+					ref.Test = testoreflect.RegularTestInfo{
+						Name:        r.caller,
+						RawBaseName: r.suiteName,
+					}
+				})
 			},
 			options...,
 		)
@@ -311,13 +323,15 @@ func (r *runner[Suite, T]) runSuiteTests(t T, s Suite, tests suiteTests[Suite, T
 
 	s.BeforeAll(t)
 
+	suiteReflection := t.unwrap().reflection.Load().Suite
+
 	suiteInfo := testoreflect.SuiteInfo{
-		Parent:   t.unwrap().reflection.Suite.Parent,
-		Name:     t.unwrap().reflection.Suite.Name,
-		Caller:   t.unwrap().reflection.Suite.Caller,
-		TestingT: t.unwrap().reflection.Suite.TestingT,
+		Parent:   suiteReflection.Parent,
+		Name:     suiteReflection.Name,
+		Caller:   suiteReflection.Caller,
+		TestingT: suiteReflection.TestingT,
 		Value:    s,
-		Hooks:    t.unwrap().reflection.Suite.Hooks,
+		Hooks:    suiteReflection.Hooks,
 	}
 
 	allTests := r.applyPlan(
@@ -338,8 +352,11 @@ func (r *runner[Suite, T]) runSuiteTests(t T, s Suite, tests suiteTests[Suite, T
 					&t,
 					func(t *testoT) {
 						t.testNamer = r.testNamer
-						t.reflection.Suite = suiteInfo
-						t.reflection.Test = test.Info
+
+						t.reflection.Modify(func(r *testoreflect.Reflection) {
+							r.Suite = suiteInfo
+							r.Test = test.Info
+						})
 
 						if test.Configure != nil {
 							test.Configure(t)
@@ -369,10 +386,12 @@ func (r *runner[Suite, T]) runSuiteTest(
 		if r := recover(); r != nil {
 			trace := string(debug.Stack())
 
-			t.unwrap().reflection.Panic = &testoreflect.PanicInfo{
-				Value: r,
-				Trace: trace,
-			}
+			t.unwrap().reflection.Modify(func(ref *testoreflect.Reflection) {
+				ref.Panic = &testoreflect.PanicInfo{
+					Value: r,
+					Trace: trace,
+				}
+			})
 
 			t.Fatalf("testo: test %q panicked: %v\n\n%s", t.Name(), r, trace)
 		}

runner_test.go

@@ -2,7 +2,9 @@ package testo
 
 import (
 	"slices"
+	"sync"
 	"testing"
+	"time"
 
 	"github.com/ozontech/testo/testoplugin"
 )
@@ -202,3 +204,59 @@ func (s TestSuite) TestFoo(t *TestT) {
 }
 
 func (s *TestSuite) TestBar(t *TestT) {}
+
+type PluginGoroutine struct {
+	*T
+
+	wg sync.WaitGroup
+}
+
+func (p *PluginGoroutine) Go(f func()) {
+	p.Helper()
+
+	p.wg.Add(1)
+
+	go func() {
+		defer p.wg.Done()
+
+		p.Helper()
+
+		f()
+	}()
+}
+
+func (p *PluginGoroutine) Plugin(testoplugin.Plugin, ...testoplugin.Option) testoplugin.Spec {
+	return testoplugin.Spec{
+		Hooks: testoplugin.Hooks{
+			AfterAll:     p.after(),
+			AfterEach:    p.after(),
+			AfterEachSub: p.after(),
+		},
+	}
+}
+
+func (p *PluginGoroutine) after() testoplugin.Hook {
+	return testoplugin.Hook{
+		Priority: testoplugin.TryFirst,
+		Func:     p.wg.Wait,
+	}
+}
+
+func TestDataRace(t *testing.T) {
+	t.Parallel()
+
+	type DataRaceT struct {
+		*T
+		*PluginGoroutine
+	}
+
+	RunTest(t, func(t DataRaceT) {
+		t.Go(func() {
+			Run(t, "inner", func(t DataRaceT) {
+				time.Sleep(time.Second)
+			})
+		})
+
+		t.Log("test")
+	})
+}

suite.go

@@ -1,6 +1,9 @@
 package testo
 
-import "github.com/ozontech/testo/testoplugin"
+import (
+	"github.com/ozontech/testo/testoplugin"
+	"github.com/ozontech/testo/testoreflect"
+)
 
 // singleton is a special (virtual) suite with a single test.
 //
@@ -71,22 +74,30 @@ type Suite[T CommonT] struct {
 
 // BeforeAll hook.
 func (Suite[T]) BeforeAll(t T) {
-	t.unwrap().reflection.Suite.Hooks.MissedBeforeAll = true
+	t.unwrap().reflection.Modify(func(r *testoreflect.Reflection) {
+		r.Suite.Hooks.MissedBeforeAll = true
+	})
 }
 
 // BeforeEach hook.
 func (Suite[T]) BeforeEach(t T) {
-	t.unwrap().reflection.Suite.Hooks.MissedBeforeEach = true
+	t.unwrap().reflection.Modify(func(r *testoreflect.Reflection) {
+		r.Suite.Hooks.MissedBeforeEach = true
+	})
 }
 
 // AfterEach hook.
 func (Suite[T]) AfterEach(t T) {
-	t.unwrap().reflection.Suite.Hooks.MissedAfterEach = true
+	t.unwrap().reflection.Modify(func(r *testoreflect.Reflection) {
+		r.Suite.Hooks.MissedAfterEach = true
+	})
 }
 
 // AfterAll hook.
 func (Suite[T]) AfterAll(t T) {
-	t.unwrap().reflection.Suite.Hooks.MissedAfterAll = true
+	t.unwrap().reflection.Modify(func(r *testoreflect.Reflection) {
+		r.Suite.Hooks.MissedAfterAll = true
+	})
 }
 
 func (Suite[T]) private() {}

t.go

@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/ozontech/testo/internal/reflectutil"
+	"github.com/ozontech/testo/internal/syncutil"
 	"github.com/ozontech/testo/internal/testnamer"
 	"github.com/ozontech/testo/testoplugin"
 	"github.com/ozontech/testo/testoreflect"
@@ -74,7 +75,7 @@ type (
 		levelOptions []testoplugin.Option
 
 		// reflection holds information for [Reflect].
-		reflection testoreflect.Reflection
+		reflection syncutil.Guarded[testoreflect.Reflection]
 
 		failureSource   atomicInt[testoreflect.TestFailureSource]
 		failureKind     atomicInt[testoreflect.TestFailureKind]
@@ -124,7 +125,7 @@ func (t *T) parallel() {
 	t.Helper()
 
 	if t.propagateParallel {
-		t.reflection.Suite.TestingT.Parallel()
+		t.reflection.Load().Suite.TestingT.Parallel()
 
 		return
 	}
@@ -409,7 +410,7 @@ func (t *T) Cleanup(f func()) {
 func (t *T) Name() string {
 	t.Helper()
 
-	return t.reflection.Test.GetName()
+	return t.reflection.Load().Test.GetName()
 }
 
 // unwrap the underlying T.
@@ -560,7 +561,7 @@ func Reflect(t CommonT) testoreflect.Reflection {
 
 	internal := t.unwrap()
 
-	info := internal.reflection
+	info := internal.reflection.Load()
 
 	info.FailureSource = internal.failureSource.Load()
 	info.FailureKind = internal.failureKind.Load()