diff --git a/Race_test.go b/Race_test.go
index 18b52a3..144bc59 100644
--- a/Race_test.go
+++ b/Race_test.go
@@ -14,6 +14,7 @@ import (
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestRace(t *testing.T) {
@@ -57,7 +58,7 @@ func TestRace(t *testing.T) {
 			testcase.Race(func() {
 				fn1Finished = true
 			}, func() {
-				fakeTB := &testcase.StubTB{}
+				fakeTB := &doubles.TB{}
 				// this only meant to represent why goroutine exit needs to be propagated.
 				fakeTB.FailNow()
 				fn2Finished = true
diff --git a/Sandbox_test.go b/Sandbox_test.go
index 6f19d8b..51f253e 100644
--- a/Sandbox_test.go
+++ b/Sandbox_test.go
@@ -7,12 +7,13 @@ import (
 
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
+	"github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/random"
 	"github.com/adamluzsi/testcase/sandbox"
 )
 
 func ExampleSandbox() {
-	stb := &testcase.StubTB{}
+	stb := &doubles.TB{}
 	outcome := testcase.Sandbox(func() {
 		// some test helper function calls fatal, which cause runtime.Goexit after marking the test failed.
 		stb.FailNow()
diff --git a/Spec.go b/Spec.go
index 71a9c08..a96f5cd 100644
--- a/Spec.go
+++ b/Spec.go
@@ -12,6 +12,7 @@ import (
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
 	"github.com/adamluzsi/testcase/internal/caller"
+	"github.com/adamluzsi/testcase/internal/teardown"
 )
 
 // NewSpec create new Spec struct that is ready for usage.
@@ -468,7 +469,7 @@ func (spec *Spec) Finish() {
 		allHookOnce = append(allHookOnce, s.hooks.AroundAll...)
 	}))
 	spec.orderer.Order(tests)
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	defer td.Finish()
 	for _, hook := range allHookOnce {
 		td.Defer(hook.Block())
diff --git a/Spec_bc_test.go b/Spec_bc_test.go
index 4a51398..001fe6f 100644
--- a/Spec_bc_test.go
+++ b/Spec_bc_test.go
@@ -6,10 +6,11 @@ import (
 
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestSpec_FriendlyVarNotDefined(t *testing.T) {
-	stub := &StubTB{}
+	stub := &doubles.TB{}
 	s := NewSpec(stub)
 	willFatalWithMessage := willFatalWithMessageFn(stub)
 
@@ -30,7 +31,7 @@ func TestSpec_FriendlyVarNotDefined(t *testing.T) {
 	})
 }
 
-func isFatalFn(stub *StubTB) func(block func()) bool {
+func isFatalFn(stub *doubles.TB) func(block func()) bool {
 	return func(block func()) bool {
 		stub.IsFailed = false
 		defer func() { stub.IsFailed = false }()
@@ -39,7 +40,7 @@ func isFatalFn(stub *StubTB) func(block func()) bool {
 	}
 }
 
-func willFatalWithMessageFn(stub *StubTB) func(tb testing.TB, blk func()) bytes.Buffer {
+func willFatalWithMessageFn(stub *doubles.TB) func(tb testing.TB, blk func()) bytes.Buffer {
 	isFatal := isFatalFn(stub)
 	return func(tb testing.TB, blk func()) bytes.Buffer {
 		stub.Logs = bytes.Buffer{}
diff --git a/Spec_test.go b/Spec_test.go
index 5eded4f..82079f9 100644
--- a/Spec_test.go
+++ b/Spec_test.go
@@ -12,6 +12,7 @@ import (
 
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
+	doubles2 "github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/internal/spechelper"
 	"github.com/adamluzsi/testcase/random"
 
@@ -257,7 +258,7 @@ func TestSpec_ParallelSafeVariableSupport(t *testing.T) {
 }
 
 func TestSpec_InvalidUsages(t *testing.T) {
-	stub := &testcase.StubTB{}
+	stub := &doubles2.TB{}
 	s := testcase.NewSpec(stub)
 	nest1Value := rand.Int()
 	nest2Value := rand.Int()
@@ -433,7 +434,7 @@ func hackCallParallel(tb testing.TB) {
 	switch tb := tb.(type) {
 	case *testing.T:
 		tb.Parallel()
-	case *internal.RecorderTB:
+	case *doubles2.RecorderTB:
 		hackCallParallel(tb.TB)
 	case *testcase.T:
 		hackCallParallel(tb.TB)
@@ -600,7 +601,7 @@ func TestSpec_LetValue_ValueDefinedAtDeclarationWithoutTheNeedOfFunctionCallback
 }
 
 func TestSpec_LetValue_mutableValuesAreNotAllowed(t *testing.T) {
-	stub := &testcase.StubTB{}
+	stub := &doubles2.TB{}
 	s := testcase.NewSpec(stub)
 
 	var finished bool
@@ -696,7 +697,7 @@ func (tb *UnknownTestingTB) Log(args ...interface{}) {
 }
 
 func TestSpec_Test_withSomethingThatImplementsTestcaseTB(t *testing.T) {
-	rtb := &internal.RecorderTB{TB: &testcase.StubTB{}}
+	rtb := &doubles2.RecorderTB{TB: &doubles2.TB{}}
 
 	var tb testcase.TBRunner = rtb // implements check
 	s := testcase.NewSpec(tb)
@@ -831,7 +832,7 @@ func TestSpec_panicDoNotLeakOutFromTestingScope(t *testing.T) {
 	var noPanic bool
 	func() {
 		defer recover()
-		rtb := &internal.RecorderTB{TB: &testcase.StubTB{}}
+		rtb := &doubles2.RecorderTB{TB: &doubles2.TB{}}
 		defer rtb.CleanupNow()
 		s := testcase.NewSpec(rtb)
 		s.Test(``, func(t *testcase.T) { panic(`die`) })
@@ -966,7 +967,7 @@ func BenchmarkTest_Spec_SkipBenchmark2(b *testing.B) {
 }
 
 type stubB struct {
-	*testcase.StubTB
+	*doubles2.TB
 	TestingB *testing.B
 }
 
@@ -975,9 +976,9 @@ func (b *stubB) Run(name string, fn func(b *testing.B)) bool {
 }
 
 func BenchmarkTest_Spec_SkipBenchmark_invalidUse(b *testing.B) {
-	stub := &testcase.StubTB{}
+	stub := &doubles2.TB{}
 	stb := &stubB{
-		StubTB:   stub,
+		TB:       stub,
 		TestingB: b,
 	}
 	s := testcase.NewSpec(stb)
@@ -1005,7 +1006,7 @@ func BenchmarkTest_Spec_Test_flaky(b *testing.B) {
 }
 
 func TestSpec_Test_FailNowWithCustom(t *testing.T) {
-	rtb := &internal.RecorderTB{TB: &testcase.StubTB{}}
+	rtb := &doubles2.RecorderTB{TB: &doubles2.TB{}}
 	s := testcase.NewSpec(rtb)
 
 	var failCount int
@@ -1020,7 +1021,7 @@ func TestSpec_Test_FailNowWithCustom(t *testing.T) {
 }
 
 func TestSpec_Test_flaky_withoutFlakyFlag_willFailAndNeverRunAgain(t *testing.T) {
-	stub := &testcase.StubTB{}
+	stub := &doubles2.TB{}
 	s := testcase.NewSpec(stub)
 	var total int
 	s.Test(``, func(t *testcase.T) { total++; t.FailNow() })
@@ -1174,7 +1175,7 @@ func TestSpec_Finish(t *testing.T) {
 }
 
 func TestSpec_Finish_finishedSpecIsImmutable(t *testing.T) {
-	stub := &testcase.StubTB{}
+	stub := &doubles2.TB{}
 	s := testcase.NewSpec(stub)
 	s.Before(func(t *testcase.T) {})
 	s.Finish()
@@ -1313,7 +1314,7 @@ func TestNewSpec_withTestingT_optionsPassed(t *testing.T) {
 func TestNewSpec_withTestcaseT_optionsPassed(t *testing.T) {
 	testcase.NewSpec(t).Test(``, func(t *testcase.T) {
 		rnd := random.New(random.CryptoSeed{})
-		stub := &testcase.StubTB{}
+		stub := &doubles2.TB{}
 		s := testcase.NewSpec(t, testcase.Flaky(time.Second))
 		s.Test(``, func(t *testcase.T) {
 			if rnd.Bool() {
diff --git a/Suite_test.go b/Suite_test.go
index 5cb56ce..77a1efe 100644
--- a/Suite_test.go
+++ b/Suite_test.go
@@ -5,12 +5,13 @@ import (
 
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
+	"github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestRunSuite(t *testing.T) {
 	t.Run(`when TB is testing.TB`, func(t *testing.T) {
 		sT := &RunContractContract{}
-		var tb testing.TB = &testcase.StubTB{}
+		var tb testing.TB = &doubles.TB{}
 		tb = testcase.NewT(tb, testcase.NewSpec(tb))
 		testcase.RunSuite(tb, sT)
 		assert.Must(t).True(sT.SpecWasCalled)
diff --git a/T.go b/T.go
index cd7d96c..6f09573 100644
--- a/T.go
+++ b/T.go
@@ -7,9 +7,8 @@ import (
 	"time"
 
 	"github.com/adamluzsi/testcase/assert"
+	"github.com/adamluzsi/testcase/internal/teardown"
 	"github.com/adamluzsi/testcase/random"
-
-	"github.com/adamluzsi/testcase/internal"
 )
 
 // NewT returns a *testcase.T prepared for the given testing.TB
@@ -37,7 +36,7 @@ func newT(tb testing.TB, spec *Spec) *T {
 		spec:     spec,
 		vars:     newVariables(),
 		tags:     spec.getTagSet(),
-		teardown: &internal.Teardown{CallerOffset: 1},
+		teardown: &teardown.Teardown{CallerOffset: 1},
 	}
 }
 
@@ -66,7 +65,7 @@ type T struct {
 	spec     *Spec
 	vars     *variables
 	tags     map[string]struct{}
-	teardown *internal.Teardown
+	teardown *teardown.Teardown
 
 	// TODO: protect it against concurrency
 	timerPaused bool
diff --git a/T_test.go b/T_test.go
index 8d3e813..d4be897 100644
--- a/T_test.go
+++ b/T_test.go
@@ -10,12 +10,11 @@ import (
 
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/contracts"
+	doubles2 "github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/sandbox"
 
 	"github.com/adamluzsi/testcase/random"
 
-	"github.com/adamluzsi/testcase/internal"
-
 	"github.com/adamluzsi/testcase"
 )
 
@@ -24,7 +23,7 @@ var _ testing.TB = &testcase.T{}
 func TestT_implementsTestingTB(t *testing.T) {
 	testcase.RunSuite(t, contracts.TestingTB{
 		Subject: func(t *testcase.T) testing.TB {
-			stub := &testcase.StubTB{}
+			stub := &doubles2.TB{}
 			t.Cleanup(stub.Finish)
 			return testcase.NewT(stub, nil)
 		},
@@ -131,7 +130,7 @@ func TestT_Defer_failNowWillNotHang(t *testing.T) {
 	go func() {
 		defer wg.Done()
 		defer recover()
-		s := testcase.NewSpec(&internal.RecorderTB{})
+		s := testcase.NewSpec(&doubles2.RecorderTB{})
 
 		s.Before(func(t *testcase.T) {
 			t.Defer(func() { t.FailNow() })
@@ -356,7 +355,7 @@ func TestT_Random(t *testing.T) {
 
 func TestT_Eventually(t *testing.T) {
 	t.Run(`with default eventually retry strategy`, func(t *testing.T) {
-		stub := &testcase.StubTB{}
+		stub := &doubles2.TB{}
 		s := testcase.NewSpec(stub)
 		s.HasSideEffect()
 		var eventuallyRan bool
@@ -373,7 +372,7 @@ func TestT_Eventually(t *testing.T) {
 	})
 
 	t.Run(`with config passed`, func(t *testing.T) {
-		stub := &testcase.StubTB{}
+		stub := &doubles2.TB{}
 		var strategyUsed bool
 		strategy := assert.RetryStrategyFunc(func(condition func() bool) {
 			strategyUsed = true
@@ -402,7 +401,7 @@ func TestNewT(t *testing.T) {
 		Init: func(t *testcase.T) int { return t.Random.Int() },
 	}
 	t.Run(`with *Spec`, func(t *testing.T) {
-		tb := &testcase.StubTB{}
+		tb := &doubles2.TB{}
 		t.Cleanup(tb.Finish)
 		s := testcase.NewSpec(tb)
 		expectedY := rnd.Int()
@@ -412,7 +411,7 @@ func TestNewT(t *testing.T) {
 		assert.Must(t).Equal(v.Get(subject), v.Get(subject), `has test variable cache`)
 	})
 	t.Run(`without *Spec`, func(t *testing.T) {
-		tb := &testcase.StubTB{}
+		tb := &doubles2.TB{}
 		t.Cleanup(tb.Finish)
 		expectedY := rnd.Int()
 		subject := testcase.NewT(tb, nil)
@@ -421,7 +420,7 @@ func TestNewT(t *testing.T) {
 		assert.Must(t).Equal(v.Get(subject), v.Get(subject), `has test variable cache`)
 	})
 	t.Run(`with *testcase.T, same returned`, func(t *testing.T) {
-		tb := &testcase.StubTB{}
+		tb := &doubles2.TB{}
 		t.Cleanup(tb.Finish)
 		tcT1 := testcase.NewT(tb, nil)
 		tcT2 := testcase.NewT(tcT1, nil)
@@ -431,7 +430,7 @@ func TestNewT(t *testing.T) {
 		assert.Must(t).Nil(testcase.NewT(nil, nil))
 	})
 	t.Run(`when NewT is retrieved multiple times, hooks executed only once`, func(t *testing.T) {
-		stb := &testcase.StubTB{}
+		stb := &doubles2.TB{}
 		s := testcase.NewSpec(stb)
 		var out []struct{}
 		s.Before(func(t *testcase.T) {
@@ -474,7 +473,7 @@ func TestT_SkipUntil(t *testing.T) {
 	rnd := random.New(rand.NewSource(time.Now().UnixNano()))
 	future := time.Now().AddDate(0, 0, 1)
 	t.Run("before SkipUntil deadline, test is skipped", func(t *testing.T) {
-		stubTB := &testcase.StubTB{}
+		stubTB := &doubles2.TB{}
 		s := testcase.NewSpec(stubTB)
 		var ran bool
 		s.Test("", func(t *testcase.T) {
@@ -488,7 +487,7 @@ func TestT_SkipUntil(t *testing.T) {
 		assert.Must(t).Contain(stubTB.Logs.String(), fmt.Sprintf(skipUntilFormat, future.Format(timeLayout)))
 	})
 	t.Run("at or after SkipUntil deadline, test is failed", func(t *testing.T) {
-		stubTB := &testcase.StubTB{}
+		stubTB := &doubles2.TB{}
 		s := testcase.NewSpec(stubTB)
 		today := time.Now().AddDate(0, 0, -1*rnd.IntN(3))
 		var ran bool
diff --git a/Var_test.go b/Var_test.go
index 60a8860..8f5e539 100644
--- a/Var_test.go
+++ b/Var_test.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/adamluzsi/testcase/assert"
+	"github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/random"
 
 	"github.com/adamluzsi/testcase"
@@ -25,7 +26,7 @@ func TestVar(t *testing.T) {
 	var testVar = testcase.Var[int]{ID: rnd.StringNWithCharset(5, "abcdefghijklmnopqrstuvwxyz")}
 	expected := rnd.Int()
 
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 	willFatal := willFatalWithMessageFn(stub)
 	willFatalWithVariableNotFoundMessage := func(s *testcase.Spec, tb testing.TB, varName string, blk func(*testcase.T)) {
 		tct := testcase.NewT(stub, s)
@@ -779,7 +780,7 @@ func TestVar_Before(t *testing.T) {
 
 func TestVar_missingID(t *testing.T) {
 	varWithoutID := testcase.Var[string]{}
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 	tct := testcase.NewT(stub, nil)
 	assert.Panic(t, func() { _ = varWithoutID.Get(tct) })
 	assert.Contain(t, stub.Logs.String(), "ID for testcase.Var[string] is missing. Maybe it's uninitialized?")
diff --git a/doubles.go b/doubles.go
new file mode 100644
index 0000000..3508307
--- /dev/null
+++ b/doubles.go
@@ -0,0 +1,8 @@
+package testcase
+
+import (
+	"github.com/adamluzsi/testcase/internal/doubles"
+)
+
+// StubTB is a stub that implements testing.TB
+type StubTB = doubles.TB
diff --git a/env_test.go b/env_test.go
index 2dddb22..8a0ec1f 100644
--- a/env_test.go
+++ b/env_test.go
@@ -6,14 +6,15 @@ import (
 
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/internal"
+	doubles2 "github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestEnvVarHelpers(t *testing.T) {
 	s := testcase.NewSpec(t)
 	s.Describe(`#SetEnv`, func(s *testcase.Spec) {
 		var (
-			recTB = testcase.Let(s, func(t *testcase.T) *internal.RecorderTB {
-				return &internal.RecorderTB{TB: &testcase.StubTB{}}
+			recTB = testcase.Let(s, func(t *testcase.T) *doubles2.RecorderTB {
+				return &doubles2.RecorderTB{TB: &doubles2.TB{}}
 			})
 			tbCleanupNow = func(t *testcase.T) { recTB.Get(t).CleanupNow() }
 			key          = testcase.Let(s, func(t *testcase.T) string {
@@ -97,7 +98,7 @@ func TestEnvVarHelpers(t *testing.T) {
 
 	s.Describe(`#UnsetEnv`, func(s *testcase.Spec) {
 		var (
-			recTB        = testcase.Let(s, func(t *testcase.T) *internal.RecorderTB { return &internal.RecorderTB{} })
+			recTB        = testcase.Let(s, func(t *testcase.T) *doubles2.RecorderTB { return &doubles2.RecorderTB{} })
 			tbCleanupNow = func(t *testcase.T) { recTB.Get(t).CleanupNow() }
 			key          = testcase.Let(s, func(t *testcase.T) string {
 				return `TESTING_DATA_` + t.Random.StringNWithCharset(5, "ABCDEFGHIJKLMNOPQRSTUVWXYZ")
diff --git a/examples_test.go b/examples_test.go
index 9bdf64f..18b9920 100644
--- a/examples_test.go
+++ b/examples_test.go
@@ -13,6 +13,7 @@ import (
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/faultinject"
+	"github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/internal/example/memory"
 	"github.com/adamluzsi/testcase/internal/example/mydomain"
 	"github.com/adamluzsi/testcase/internal/example/spechelper"
@@ -481,7 +482,7 @@ func ExampleT_should() {
 }
 
 func ExampleStubTB_testingATestHelper() {
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 	stub.Log("hello", "world")
 	fmt.Println(stub.Logs.String())
 
@@ -905,8 +906,8 @@ func ExampleSpec_Let_testingDouble() {
 	var t *testing.T
 	s := testcase.NewSpec(t)
 
-	stubTB := testcase.Let(s, func(t *testcase.T) *testcase.StubTB {
-		stub := &testcase.StubTB{}
+	stubTB := testcase.Let(s, func(t *testcase.T) *doubles.TB {
+		stub := &doubles.TB{}
 		t.Defer(stub.Finish)
 		return stub
 	})
diff --git a/hooks_test.go b/hooks_test.go
index 4330fc6..fd76f96 100644
--- a/hooks_test.go
+++ b/hooks_test.go
@@ -7,6 +7,7 @@ import (
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestSpec_Before_Ordered(t *testing.T) {
@@ -126,7 +127,7 @@ func TestSpec_AroundAll_blkRunsOnlyOnce(t *testing.T) {
 func TestSpec_BeforeAll_failIfDefinedAfterTestCases(t *testing.T) {
 	var isAnyOfTheTestCaseRan bool
 	blk := func(t *testcase.T) { isAnyOfTheTestCaseRan = true }
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 
 	internal.RecoverGoexit(func() {
 		s := testcase.NewSpec(stub)
@@ -143,7 +144,7 @@ func TestSpec_BeforeAll_failIfDefinedAfterTestCases(t *testing.T) {
 func TestSpec_AfterAll_failIfDefinedAfterTestCases(t *testing.T) {
 	var isAnyOfTheTestCaseRan bool
 	blk := func(t *testcase.T) { isAnyOfTheTestCaseRan = true }
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 
 	internal.RecoverGoexit(func() {
 		s := testcase.NewSpec(stub)
@@ -160,7 +161,7 @@ func TestSpec_AfterAll_failIfDefinedAfterTestCases(t *testing.T) {
 func TestSpec_AroundAll_failIfDefinedAfterTestCases(t *testing.T) {
 	var isAnyOfTheTestCaseRan bool
 	blk := func(t *testcase.T) { isAnyOfTheTestCaseRan = true }
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 
 	internal.RecoverGoexit(func() {
 		s := testcase.NewSpec(stub)
diff --git a/internal/backward.go b/internal/backward.go
new file mode 100644
index 0000000..257b043
--- /dev/null
+++ b/internal/backward.go
@@ -0,0 +1,9 @@
+package internal
+
+import (
+	"github.com/adamluzsi/testcase/internal/doubles"
+	"github.com/adamluzsi/testcase/internal/teardown"
+)
+
+type RecorderTB = doubles.RecorderTB
+type Teardown = teardown.Teardown
diff --git a/internal/RecorderTB.go b/internal/doubles/RecorderTB.go
similarity index 97%
rename from internal/RecorderTB.go
rename to internal/doubles/RecorderTB.go
index 1f055ed..2da326d 100644
--- a/internal/RecorderTB.go
+++ b/internal/doubles/RecorderTB.go
@@ -1,9 +1,11 @@
-package internal
+package doubles
 
 import (
 	"runtime"
 	"sync"
 	"testing"
+
+	"github.com/adamluzsi/testcase/internal/teardown"
 )
 
 type RecorderTB struct {
@@ -60,7 +62,7 @@ func (rtb *RecorderTB) Forward() {
 
 func (rtb *RecorderTB) CleanupNow() {
 	defer rtb.withPassthrough()()
-	td := &Teardown{}
+	td := &teardown.Teardown{}
 	for _, event := range rtb.records {
 		if event.Cleanup != nil && !event.Skip {
 			td.Defer(event.Cleanup)
diff --git a/internal/RecorderTB_test.go b/internal/doubles/RecorderTB_test.go
similarity index 95%
rename from internal/RecorderTB_test.go
rename to internal/doubles/RecorderTB_test.go
index 3ff8b46..04a7520 100644
--- a/internal/RecorderTB_test.go
+++ b/internal/doubles/RecorderTB_test.go
@@ -1,4 +1,4 @@
-package internal_test
+package doubles_test
 
 import (
 	"fmt"
@@ -10,22 +10,22 @@ import (
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/contracts"
-	"github.com/adamluzsi/testcase/internal"
+	doubles2 "github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/sandbox"
 )
 
-var _ testcase.TBRunner = &internal.RecorderTB{}
+var _ testcase.TBRunner = &doubles2.RecorderTB{}
 
 func TestRecorderTB(t *testing.T) {
 	s := testcase.NewSpec(t)
 
-	stubTB := testcase.Let(s, func(t *testcase.T) *testcase.StubTB {
-		stub := &testcase.StubTB{}
+	stubTB := testcase.Let(s, func(t *testcase.T) *doubles2.TB {
+		stub := &doubles2.TB{}
 		t.Cleanup(stub.Finish)
 		return stub
 	})
-	recorder := testcase.Let(s, func(t *testcase.T) *internal.RecorderTB {
-		return &internal.RecorderTB{TB: stubTB.Get(t)}
+	recorder := testcase.Let(s, func(t *testcase.T) *doubles2.RecorderTB {
+		return &doubles2.RecorderTB{TB: stubTB.Get(t)}
 	})
 
 	expectToExitGoroutine := func(t *testcase.T, fn func()) {
@@ -65,7 +65,7 @@ func TestRecorderTB(t *testing.T) {
 		})
 	}
 
-	thenUnderlyingTBWillExpect := func(s *testcase.Spec, subject func(t *testcase.T), fn func(t *testcase.T, stub *testcase.StubTB)) {
+	thenUnderlyingTBWillExpect := func(s *testcase.Spec, subject func(t *testcase.T), fn func(t *testcase.T, stub *doubles2.TB)) {
 		s.Then(`on #Forward, the method call is forwarded to the received testing.TB`, func(t *testcase.T) {
 			fn(t, stubTB.Get(t))
 			subject(t)
@@ -84,7 +84,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.True(stub.IsFailed)
 			})
@@ -98,7 +98,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.True(stub.IsFailed)
 			})
@@ -112,7 +112,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.Contain(stub.Logs.String(), `foo`)
 			})
@@ -126,7 +126,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.Contain(stub.Logs.String(), `errorf -`)
 			})
@@ -140,7 +140,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.Contain(stub.Logs.String(), `fatal`)
 			})
@@ -154,7 +154,7 @@ func TestRecorderTB(t *testing.T) {
 
 		thenTBWillMarkedAsFailed(s, subject)
 
-		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *testcase.StubTB) {
+		thenUnderlyingTBWillExpect(s, subject, func(t *testcase.T, stub *doubles2.TB) {
 			t.Cleanup(func() {
 				t.Must.Contain(stub.Logs.String(), `fatalf -`)
 			})
@@ -180,7 +180,7 @@ func TestRecorderTB(t *testing.T) {
 					assert.Must(t).True(subject(t))
 				})
 
-				thenUnderlyingTBWillExpect(s, func(t *testcase.T) { _ = subject(t) }, func(t *testcase.T, stub *testcase.StubTB) {
+				thenUnderlyingTBWillExpect(s, func(t *testcase.T) { _ = subject(t) }, func(t *testcase.T, stub *doubles2.TB) {
 					t.Cleanup(func() {
 						t.Must.False(stub.Failed(), "expect that IsFailed don't affect the testing.TB")
 					})
@@ -194,7 +194,7 @@ func TestRecorderTB(t *testing.T) {
 					assert.Must(t).False(subject(t))
 				})
 
-				thenUnderlyingTBWillExpect(s, func(t *testcase.T) { _ = subject(t) }, func(t *testcase.T, stub *testcase.StubTB) {
+				thenUnderlyingTBWillExpect(s, func(t *testcase.T) { _ = subject(t) }, func(t *testcase.T, stub *doubles2.TB) {
 					t.Cleanup(func() {
 						t.Must.False(stub.Failed())
 					})
@@ -605,9 +605,9 @@ func TestRecorderTB(t *testing.T) {
 func TestRecorderTB_implementsCustomTB(t *testing.T) {
 	testcase.RunSuite(t, contracts.CustomTB{
 		Subject: func(t *testcase.T) testcase.TBRunner {
-			stub := &testcase.StubTB{}
+			stub := &doubles2.TB{}
 			t.Defer(stub.Finish)
-			rtb := &internal.RecorderTB{TB: stub}
+			rtb := &doubles2.RecorderTB{TB: stub}
 			rtb.Config.Passthrough = true
 			return rtb
 		},
@@ -616,8 +616,8 @@ func TestRecorderTB_implementsCustomTB(t *testing.T) {
 
 func TestRecorderTB_Record_ConcurrentAccess(t *testing.T) {
 	var (
-		stub = &testcase.StubTB{}
-		rtb  = &internal.RecorderTB{TB: stub}
+		stub = &doubles2.TB{}
+		rtb  = &doubles2.RecorderTB{TB: stub}
 	)
 
 	var wg sync.WaitGroup
diff --git a/StubTB.go b/internal/doubles/TB.go
similarity index 60%
rename from StubTB.go
rename to internal/doubles/TB.go
index ef5313f..dd2428f 100644
--- a/StubTB.go
+++ b/internal/doubles/TB.go
@@ -1,4 +1,4 @@
-package testcase
+package doubles
 
 import (
 	"bytes"
@@ -9,10 +9,10 @@ import (
 	"testing"
 	"time"
 
-	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/teardown"
 )
 
-type StubTB struct {
+type TB struct {
 	// TB is an optional value here.
 	// If provided, some default behaviour might be taken from it, like TempDir.
 	//
@@ -26,94 +26,94 @@ type StubTB struct {
 	StubName    string
 	StubTempDir string
 
-	td    internal.Teardown
+	td    teardown.Teardown
 	mutex sync.Mutex
 }
 
-func (m *StubTB) Finish() {
+func (m *TB) Finish() {
 	m.td.Finish()
 }
 
-func (m *StubTB) Cleanup(f func()) {
+func (m *TB) Cleanup(f func()) {
 	m.td.Defer(f)
 }
 
-func (m *StubTB) Error(args ...any) {
+func (m *TB) Error(args ...any) {
 	m.appendLogs(fmt.Sprintln(args...))
 	m.Fail()
 }
 
-func (m *StubTB) Errorf(format string, args ...any) {
+func (m *TB) Errorf(format string, args ...any) {
 	m.appendLogs(fmt.Sprintf(format+"\n", args...))
 	m.Fail()
 }
 
-func (m *StubTB) Fail() {
+func (m *TB) Fail() {
 	m.IsFailed = true
 }
 
-func (m *StubTB) FailNow() {
+func (m *TB) FailNow() {
 	m.Fail()
 	runtime.Goexit()
 }
 
-func (m *StubTB) Failed() bool {
+func (m *TB) Failed() bool {
 	return m.IsFailed
 }
 
-func (m *StubTB) Fatal(args ...any) {
+func (m *TB) Fatal(args ...any) {
 	m.appendLogs(fmt.Sprintln(args...))
 	m.FailNow()
 }
 
-func (m *StubTB) Fatalf(format string, args ...any) {
+func (m *TB) Fatalf(format string, args ...any) {
 	m.appendLogs(fmt.Sprintf(format+"\n", args...))
 	m.FailNow()
 }
 
-func (m *StubTB) Helper() {}
+func (m *TB) Helper() {}
 
-func (m *StubTB) appendLogs(msg string) {
+func (m *TB) appendLogs(msg string) {
 	m.mutex.Lock()
 	defer m.mutex.Unlock()
 	_, _ = fmt.Fprint(&m.Logs, msg)
 }
 
-func (m *StubTB) Log(args ...any) {
+func (m *TB) Log(args ...any) {
 	m.appendLogs(fmt.Sprintln(args...))
 }
 
-func (m *StubTB) Logf(format string, args ...any) {
+func (m *TB) Logf(format string, args ...any) {
 	m.appendLogs(fmt.Sprintf(format+"\n", args...))
 }
 
-func (m *StubTB) Name() string {
+func (m *TB) Name() string {
 	if m.StubName == "" {
 		m.StubName = fmt.Sprintf("%d", time.Now().UnixNano())
 	}
 	return m.StubName
 }
 
-func (m *StubTB) Skip(args ...any) {
+func (m *TB) Skip(args ...any) {
 	m.Log(args...)
 	m.SkipNow()
 }
 
-func (m *StubTB) SkipNow() {
+func (m *TB) SkipNow() {
 	m.IsSkipped = true
 	runtime.Goexit()
 }
 
-func (m *StubTB) Skipf(format string, args ...any) {
+func (m *TB) Skipf(format string, args ...any) {
 	m.Logf(format, args...)
 	m.SkipNow()
 }
 
-func (m *StubTB) Skipped() bool {
+func (m *TB) Skipped() bool {
 	return m.IsSkipped
 }
 
-func (m *StubTB) TempDir() string {
+func (m *TB) TempDir() string {
 	if m.StubTempDir != "" {
 		return m.StubTempDir
 	}
diff --git a/StubTB_test.go b/internal/doubles/TB_test.go
similarity index 97%
rename from StubTB_test.go
rename to internal/doubles/TB_test.go
index d0b6cb3..3f4c097 100644
--- a/StubTB_test.go
+++ b/internal/doubles/TB_test.go
@@ -1,4 +1,4 @@
-package testcase_test
+package doubles_test
 
 import (
 	"os"
@@ -9,13 +9,14 @@ import (
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/contracts"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/doubles"
 )
 
 func TestStubTB(t *testing.T) {
 	s := testcase.NewSpec(t)
 
-	var stub = testcase.Let(s, func(t *testcase.T) *testcase.StubTB {
-		return &testcase.StubTB{}
+	var stub = testcase.Let(s, func(t *testcase.T) *doubles.TB {
+		return &doubles.TB{}
 	})
 
 	s.Test(`.Cleanup + .Finish`, func(t *testcase.T) {
@@ -227,7 +228,7 @@ func TestStubTB(t *testing.T) {
 func TestStubTB_implementsTestingTB(t *testing.T) {
 	testcase.RunSuite(t, contracts.TestingTB{
 		Subject: func(t *testcase.T) testing.TB {
-			stb := &testcase.StubTB{}
+			stb := &doubles.TB{}
 			t.Cleanup(stb.Finish)
 			return stb
 		},
diff --git a/internal/offset_helper_test.go b/internal/offset_helper_test.go
deleted file mode 100644
index 4d30f6e..0000000
--- a/internal/offset_helper_test.go
+++ /dev/null
@@ -1,5 +0,0 @@
-package internal_test
-
-import "github.com/adamluzsi/testcase/internal"
-
-func offsetHelper(td *internal.Teardown, fn interface{}, args ...interface{}) { td.Defer(fn, args...) }
diff --git a/internal/Teardown.go b/internal/teardown/Teardown.go
similarity index 90%
rename from internal/Teardown.go
rename to internal/teardown/Teardown.go
index 1ee825d..705b30d 100644
--- a/internal/Teardown.go
+++ b/internal/teardown/Teardown.go
@@ -1,10 +1,12 @@
-package internal
+package teardown
 
 import (
 	"fmt"
 	"reflect"
 	"runtime"
 	"sync"
+
+	"github.com/adamluzsi/testcase/sandbox"
 )
 
 type Teardown struct {
@@ -123,7 +125,18 @@ func (td *Teardown) isEmpty() bool {
 func (td *Teardown) add(fn func()) {
 	td.mutex.Lock()
 	defer td.mutex.Unlock()
-	td.fns = append(td.fns, func() { RecoverGoexit(fn) })
+	td.fns = append(td.fns, func() { td.recoverGoexit(fn) })
+}
+
+func (td *Teardown) recoverGoexit(fn func()) sandbox.RunOutcome {
+	runOutcome := sandbox.Run(fn)
+	if runOutcome.Goexit { // ignore goexit
+		return runOutcome
+	}
+	if !runOutcome.OK { // propagate panic
+		panic(runOutcome.PanicValue)
+	}
+	return runOutcome
 }
 
 func (td *Teardown) run() {
diff --git a/internal/Teardown_test.go b/internal/teardown/Teardown_test.go
similarity index 92%
rename from internal/Teardown_test.go
rename to internal/teardown/Teardown_test.go
index b93c51f..f0bbe12 100644
--- a/internal/Teardown_test.go
+++ b/internal/teardown/Teardown_test.go
@@ -1,4 +1,4 @@
-package internal_test
+package teardown_test
 
 import (
 	"context"
@@ -9,10 +9,11 @@ import (
 	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/teardown"
 )
 
 func TestTeardown_Defer_order(t *testing.T) {
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	var res []int
 	td.Defer(func() { res = append(res, 3) })
 	td.Defer(func() { res = append(res, 2) })
@@ -24,7 +25,7 @@ func TestTeardown_Defer_order(t *testing.T) {
 }
 
 func TestTeardown_Defer_commonFunctionSignatures(t *testing.T) {
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	var res []int
 	td.Defer(func() error { res = append(res, 1); return nil })
 	td.Defer(func() { res = append(res, 0) })
@@ -57,7 +58,7 @@ func TestTeardown_Defer_ignoresGoExit(t *testing.T) {
 
 	var a, b, c bool
 	internal.RecoverGoexit(func() {
-		td := &internal.Teardown{}
+		td := &teardown.Teardown{}
 		defer td.Finish()
 		td.Defer(func() {
 			a = true
@@ -82,7 +83,7 @@ func TestTeardown_Defer_panic(t *testing.T) {
 	var a, b, c bool
 	const expectedPanicMessage = `boom`
 
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	td.Defer(func() { a = true })
 	td.Defer(func() { b = true; panic(expectedPanicMessage) })
 	td.Defer(func() { c = true })
@@ -101,7 +102,7 @@ func TestTeardown_Defer_panic(t *testing.T) {
 
 func TestTeardown_Defer_withinCleanup(t *testing.T) {
 	var a, b, c bool
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	td.Defer(func() {
 		a = true
 		td.Defer(func() {
@@ -119,7 +120,7 @@ func TestTeardown_Defer_withinCleanup(t *testing.T) {
 }
 
 func TestTeardown_Defer_args(t *testing.T) {
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	t.Run(`arg is primitive type`, func(t *testing.T) {
 		fn := func(_ int) {}
 
@@ -149,7 +150,7 @@ func TestTeardown_Defer_args(t *testing.T) {
 	})
 
 	t.Run(`pass by value`, func(t *testing.T) {
-		td := &internal.Teardown{}
+		td := &teardown.Teardown{}
 		v := 42
 		var out int
 		td.Defer(func(n int) { out = n }, v)
@@ -192,7 +193,7 @@ func TestTeardown_Defer_withVariadicArgument_argumentPassed(t *testing.T) {
 
 func TestT_Defer_withArgumentsButArgumentCountMismatch(t *testing.T) {
 	var subject = func() {
-		td := &internal.Teardown{}
+		td := &teardown.Teardown{}
 		td.Defer(func(text string) {}, `this would be ok`, `but this extra argument is not ok`)
 	}
 
@@ -211,7 +212,7 @@ func TestT_Defer_withArgumentsButArgumentCountMismatch(t *testing.T) {
 		type notContextForSure struct{}
 		var fn = func(ctx context.Context) {}
 		var subject = func(ctx interface{}) {
-			td := &internal.Teardown{}
+			td := &teardown.Teardown{}
 			td.Defer(fn, ctx)
 		}
 		assert.Must(t).Panic(func() { subject(notContextForSure{}) })
@@ -235,7 +236,7 @@ func TestTeardown_Defer_runtimeGoexit(t *testing.T) {
 	internal.RecoverGoexit(func() {
 		var ran bool
 		defer func() { assert.Must(t).True(ran) }()
-		td := &internal.Teardown{}
+		td := &teardown.Teardown{}
 		td.Defer(func() { ran = true })
 		td.Defer(func() { runtime.Goexit() })
 		td.Finish()
@@ -246,16 +247,16 @@ func TestTeardown_Defer_runtimeGoexit(t *testing.T) {
 
 func TestTeardown_Defer_CallerOffset(t *testing.T) {
 	var subject = func(offset int) string {
-		td := &internal.Teardown{CallerOffset: offset}
+		td := &teardown.Teardown{CallerOffset: offset}
 		return getPanicMessage(t, func() { offsetHelper(td, func(int) {}, "42") })
 	}
-	assert.Must(t).Contain(subject(0), `offset_helper_test.go:5`)
+	assert.Must(t).Contain(subject(0), `offset_helper_test.go:7`)
 	assert.Must(t).Contain(subject(1), `Teardown_test.go`)
 }
 
 func TestTeardown_Defer_isThreadSafe(t *testing.T) {
 	var (
-		td       = &internal.Teardown{}
+		td       = &teardown.Teardown{}
 		out      = &sync.Map{}
 		sampling = runtime.NumCPU() * 42
 
@@ -290,7 +291,7 @@ func TestTeardown_Defer_isThreadSafe(t *testing.T) {
 
 func TestTeardown_Finish_idempotent(t *testing.T) {
 	var count int
-	td := &internal.Teardown{}
+	td := &teardown.Teardown{}
 	td.Defer(func() { count++ })
 	td.Finish()
 	td.Finish()
diff --git a/internal/teardown/offset_helper_test.go b/internal/teardown/offset_helper_test.go
new file mode 100644
index 0000000..c188639
--- /dev/null
+++ b/internal/teardown/offset_helper_test.go
@@ -0,0 +1,7 @@
+package teardown_test
+
+import (
+	"github.com/adamluzsi/testcase/internal/teardown"
+)
+
+func offsetHelper(td *teardown.Teardown, fn interface{}, args ...interface{}) { td.Defer(fn, args...) }
diff --git a/let_test.go b/let_test.go
index 783d51e..0bec479 100644
--- a/let_test.go
+++ b/let_test.go
@@ -9,6 +9,7 @@ import (
 	"github.com/adamluzsi/testcase/assert"
 	"github.com/adamluzsi/testcase/httpspec"
 	"github.com/adamluzsi/testcase/internal/caller"
+	"github.com/adamluzsi/testcase/internal/doubles"
 	"github.com/adamluzsi/testcase/sandbox"
 )
 
@@ -102,7 +103,7 @@ func TestLet_posName(t *testing.T) {
 
 func TestLet_withNilBlock(tt *testing.T) {
 	it := assert.MakeIt(tt)
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 	defer stub.Finish()
 	s := testcase.NewSpec(stub)
 	v := testcase.Let[int](s, nil)
@@ -121,7 +122,7 @@ func TestLet_withNilBlock(tt *testing.T) {
 
 func TestLetValue_withNil(tt *testing.T) {
 	it := assert.MakeIt(tt)
-	stub := &testcase.StubTB{}
+	stub := &doubles.TB{}
 	defer stub.Finish()
 	s := testcase.NewSpec(stub)
 	v := testcase.Let[[]int](s, nil)
diff --git a/spec_helper_test.go b/spec_helper_test.go
index c0c9f69..379a0fe 100644
--- a/spec_helper_test.go
+++ b/spec_helper_test.go
@@ -4,8 +4,8 @@ import (
 	"bytes"
 	"testing"
 
-	"github.com/adamluzsi/testcase"
 	"github.com/adamluzsi/testcase/internal"
+	"github.com/adamluzsi/testcase/internal/doubles"
 
 	"github.com/adamluzsi/testcase/assert"
 )
@@ -35,7 +35,7 @@ func unsupported(tb testing.TB) {
 	tb.Skip(`unsupported`)
 }
 
-func isFatalFn(stub *testcase.StubTB) func(block func()) bool {
+func isFatalFn(stub *doubles.TB) func(block func()) bool {
 	return func(block func()) bool {
 		stub.IsFailed = false
 		defer func() { stub.IsFailed = false }()
@@ -48,7 +48,7 @@ func isFatalFn(stub *testcase.StubTB) func(block func()) bool {
 	}
 }
 
-func willFatalWithMessageFn(stub *testcase.StubTB) func(tb testing.TB, blk func()) string {
+func willFatalWithMessageFn(stub *doubles.TB) func(tb testing.TB, blk func()) string {
 	isFatal := isFatalFn(stub)
 	return func(tb testing.TB, blk func()) string {
 		stub.Logs = bytes.Buffer{}