diff --git a/env.go b/env.go
index e66c7ca..e1e1e7f 100644
--- a/env.go
+++ b/env.go
@@ -299,7 +299,10 @@ func (e *EnvT) fixtureCallWrapper(key cacheKey, f FixtureCallbackFunc, opt *Fixt
 		e.m.Unlock()
 
 		if si == nil {
-			e.t.Fatalf("Unexpected scope. Create env for test %q", scopeName)
+			if opt.Scope == ScopePackage {
+				e.t.Fatalf("Initialize package scope before use ", scopeName)
+			}
+			e.t.Fatalf("Unexpected scope: %q", scopeName)
 			// not reachable
 			return nil, nil
 		}
diff --git a/examples/simple_main_test/example_test.go b/examples/simple_main_test/example_test.go
new file mode 100644
index 0000000..9e47708
--- /dev/null
+++ b/examples/simple_main_test/example_test.go
@@ -0,0 +1,41 @@
+//go:build go1.18
+// +build go1.18
+
+package simple_main_test
+
+import (
+	"github.com/rekby/fixenv"
+	"math/rand"
+	"testing"
+)
+
+var global int = -1
+
+func FSingleRandom(e fixenv.Env) int {
+	var f fixenv.GenericFixtureFunction[int] = func() (*fixenv.GenericResult[int], error) {
+		return fixenv.NewGenericResult(rand.Int()), nil
+	}
+	return fixenv.CacheResult(e, f, fixenv.CacheOptions{Scope: fixenv.ScopePackage})
+}
+
+func TestFirst(t *testing.T) {
+	e := fixenv.New(t)
+	if global == -1 {
+		global = FSingleRandom(e)
+	}
+
+	if singleRnd := FSingleRandom(e); singleRnd != global {
+		t.Fatalf("%v != %v", singleRnd, global)
+	}
+}
+
+func TestSecond(t *testing.T) {
+	e := fixenv.New(t)
+	if global == -1 {
+		global = FSingleRandom(e)
+	}
+
+	if singleRnd := FSingleRandom(e); singleRnd != global {
+		t.Fatalf("%v != %v", singleRnd, global)
+	}
+}
diff --git a/examples/simple_main_test/testmain_test.go b/examples/simple_main_test/testmain_test.go
new file mode 100644
index 0000000..42580a0
--- /dev/null
+++ b/examples/simple_main_test/testmain_test.go
@@ -0,0 +1,11 @@
+package simple_main
+
+import (
+	"github.com/rekby/fixenv"
+	"os"
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	os.Exit(fixenv.RunTests(m))
+}
diff --git a/maintest.go b/maintest.go
index 9c54d51..0cd83e9 100644
--- a/maintest.go
+++ b/maintest.go
@@ -1,11 +1,15 @@
 package fixenv
 
 import (
+	"errors"
 	"fmt"
 	"log"
 	"sync"
 )
 
+var errPackageEnvInitializedSecondTime = errors.New("package env initialize second time. It must be call not more then once. ")
+var errTooManyOptionalArgs = errors.New("allow not more then one optional arg")
+
 // FatalfFunction function signature of Fatalf
 type FatalfFunction func(format string, args ...interface{})
 
@@ -34,18 +38,52 @@ type CreateMainTestEnvOpts struct {
 	SkipNow SkipNowFunction
 }
 
+// packageLevelVirtualTest now used for tests only
+var lastPackageLevelVirtualTest *virtualTest
+
 // CreateMainTestEnv called from TestMain for create global environment.
 // It need only for use ScopePackage cache scope.
 // If ScopePackage not used - no need to create main env.
 func CreateMainTestEnv(opts *CreateMainTestEnvOpts) (env *EnvT, tearDown func()) {
+	// TODO: handle second time initialize
 	globalMutex.Lock()
 	packageLevelVirtualTest := newVirtualTest(opts)
+	lastPackageLevelVirtualTest = packageLevelVirtualTest
 	globalMutex.Unlock()
 
 	env = New(packageLevelVirtualTest) // register global test for env
 	return env, packageLevelVirtualTest.cleanup
 }
 
+// RunTests runs the tests. It returns an exit code to pass to os.Exit.
+//
+// Usage:
+// declare in _test file TestMain function:
+//
+// func TestMain(m *testing.M) {
+//	 os.Exit(fixenv.RunTests(m))
+// }
+func RunTests(m RunTestsI, opts ...CreateMainTestEnvOpts) int {
+	var options *CreateMainTestEnvOpts
+	switch len(opts) {
+	case 0:
+		// pass
+	case 1:
+		options = &opts[0]
+	default:
+		panic(errTooManyOptionalArgs)
+	}
+
+	_, cancel := CreateMainTestEnv(options)
+	defer cancel()
+	return m.Run()
+}
+
+type RunTestsI interface {
+	// Run runs the tests. It returns an exit code to pass to os.Exit.
+	Run() (code int)
+}
+
 // virtualTest implement T interface for global env scope
 type virtualTest struct {
 	m       sync.Mutex
diff --git a/maintest_test.go b/maintest_test.go
index aa44dc7..ddea0f2 100644
--- a/maintest_test.go
+++ b/maintest_test.go
@@ -1,6 +1,7 @@
 package fixenv
 
 import (
+	"errors"
 	"runtime"
 	"sync"
 	"testing"
@@ -76,3 +77,89 @@ func TestCreateMainTestEnv(t *testing.T) {
 		})
 	})
 }
+
+func TestRunTests(t *testing.T) {
+	expectedReturnCode := 123
+
+	checkInitialized := func(t *testing.T) {
+		t.Helper()
+
+		globalMutex.Lock()
+		defer globalMutex.Unlock()
+
+		if _, ok := globalScopeInfo[packageScopeName]; !ok {
+			t.Fatal()
+		}
+	}
+	cleanGlobalState := func() {
+		globalMutex.Lock()
+		defer globalMutex.Unlock()
+
+		delete(globalScopeInfo, packageScopeName)
+	}
+
+	t.Run("without options", func(t *testing.T) {
+		m := &mTestsMock{
+			returnCode: expectedReturnCode,
+			run: func() {
+				checkInitialized(t)
+			},
+		}
+
+		if res := RunTests(m); res != expectedReturnCode {
+			t.Fatalf("%v != %v", res, expectedReturnCode)
+		}
+		cleanGlobalState()
+	})
+	t.Run("with options", func(t *testing.T) {
+		m := &mTestsMock{
+			returnCode: expectedReturnCode,
+			run: func() {
+				checkInitialized(t)
+				lastPackageLevelVirtualTest.SkipNow()
+			},
+		}
+
+		called := false
+		RunTests(m, CreateMainTestEnvOpts{SkipNow: func() {
+			called = true
+		}})
+		if !called {
+			t.Fatal()
+		}
+		cleanGlobalState()
+	})
+	t.Run("with two options", func(t *testing.T) {
+		defer func() {
+			cleanGlobalState()
+
+			rec := recover()
+			if !errors.Is(rec.(error), errTooManyOptionalArgs) {
+				t.Fatal(rec)
+			}
+		}()
+		m := &mTestsMock{
+			run: func() {
+				checkInitialized(t)
+			},
+		}
+		RunTests(m, CreateMainTestEnvOpts{}, CreateMainTestEnvOpts{})
+	})
+}
+
+type mTestsMock struct {
+	runCalled  bool
+	returnCode int
+	run        func()
+}
+
+func (r *mTestsMock) Run() (code int) {
+	r.runCalled = true
+	if r.run != nil {
+		r.run()
+	}
+	return r.returnCode
+}
+
+// check interface implementation
+var _ RunTestsI = &mTestsMock{}