diff --git a/internal/testutils/test_utils.go b/internal/testutils/test_utils.go
index 942dab7..8673ff4 100644
--- a/internal/testutils/test_utils.go
+++ b/internal/testutils/test_utils.go
@@ -197,15 +197,12 @@ func AssertQueryPanicErr(t *testing.T, stmt jet.Statement, db qrm.DB, dest inter
 }
 
 // AssertFileContent check if file content at filePath contains expectedContent text.
-func AssertFileContent(t *testing.T, filePath string, contentBegin string, expectedContent string) {
+func AssertFileContent(t *testing.T, filePath string, expectedContent string) {
 	enumFileData, err := ioutil.ReadFile(filePath)
 
-	assert.NoError(t, err)
+	require.NoError(t, err)
 
-	beginIndex := bytes.Index(enumFileData, []byte(contentBegin))
-
-	//AssertDeepEqual(t, string(enumFileData[beginIndex:]), expectedContent)
-	require.Equal(t, string(enumFileData[beginIndex:]), expectedContent)
+	require.Equal(t, "\n"+string(enumFileData), expectedContent)
 }
 
 // AssertFileNamesEqual check if all filesInfos are contained in fileNames
diff --git a/tests/mysql/generator_test.go b/tests/mysql/generator_test.go
index 59df9a1..f28c5c1 100644
--- a/tests/mysql/generator_test.go
+++ b/tests/mysql/generator_test.go
@@ -67,7 +67,7 @@ func assertGeneratedFiles(t *testing.T) {
 		"customer.go", "film.go", "film_actor.go", "film_category.go", "film_text.go", "inventory.go", "language.go",
 		"payment.go", "rental.go", "staff.go", "store.go")
 
-	testutils.AssertFileContent(t, genTestDir3+"/dvds/table/actor.go", "\npackage table", actorSQLBuilderFile)
+	testutils.AssertFileContent(t, genTestDir3+"/dvds/table/actor.go", actorSQLBuilderFile)
 
 	// View SQL Builder files
 	viewSQLBuilderFiles, err := ioutil.ReadDir(genTestDir3 + "/dvds/view")
@@ -76,14 +76,14 @@ func assertGeneratedFiles(t *testing.T) {
 	testutils.AssertFileNamesEqual(t, viewSQLBuilderFiles, "actor_info.go", "film_list.go", "nicer_but_slower_film_list.go",
 		"sales_by_film_category.go", "customer_list.go", "sales_by_store.go", "staff_list.go")
 
-	testutils.AssertFileContent(t, genTestDir3+"/dvds/view/actor_info.go", "\npackage view", actorInfoSQLBuilderFile)
+	testutils.AssertFileContent(t, genTestDir3+"/dvds/view/actor_info.go", actorInfoSQLBuilderFile)
 
 	// Enums SQL Builder files
 	enumFiles, err := ioutil.ReadDir(genTestDir3 + "/dvds/enum")
 	assert.NoError(t, err)
 
 	testutils.AssertFileNamesEqual(t, enumFiles, "film_rating.go", "film_list_rating.go", "nicer_but_slower_film_list_rating.go")
-	testutils.AssertFileContent(t, genTestDir3+"/dvds/enum/film_rating.go", "\npackage enum", mpaaRatingEnumFile)
+	testutils.AssertFileContent(t, genTestDir3+"/dvds/enum/film_rating.go", mpaaRatingEnumFile)
 
 	// Model files
 	modelFiles, err := ioutil.ReadDir(genTestDir3 + "/dvds/model")
@@ -96,10 +96,17 @@ func assertGeneratedFiles(t *testing.T) {
 		"actor_info.go", "film_list.go", "nicer_but_slower_film_list.go", "sales_by_film_category.go",
 		"customer_list.go", "sales_by_store.go", "staff_list.go")
 
-	testutils.AssertFileContent(t, genTestDir3+"/dvds/model/actor.go", "\npackage model", actorModelFile)
+	testutils.AssertFileContent(t, genTestDir3+"/dvds/model/actor.go", actorModelFile)
 }
 
 var mpaaRatingEnumFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package enum
 
 import "github.com/go-jet/jet/mysql"
@@ -120,6 +127,13 @@ var FilmRating = &struct {
 `
 
 var actorSQLBuilderFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package table
 
 import (
@@ -187,6 +201,13 @@ func newActorTableImpl(schemaName, tableName string) actorTable {
 `
 
 var actorModelFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package model
 
 import (
@@ -202,6 +223,13 @@ type Actor struct {
 `
 
 var actorInfoSQLBuilderFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package view
 
 import (
diff --git a/tests/postgres/generator_test.go b/tests/postgres/generator_test.go
index 71f4f8f..a9e771d 100644
--- a/tests/postgres/generator_test.go
+++ b/tests/postgres/generator_test.go
@@ -101,7 +101,7 @@ func assertGeneratedFiles(t *testing.T) {
 		"customer.go", "film.go", "film_actor.go", "film_category.go", "inventory.go", "language.go",
 		"payment.go", "rental.go", "staff.go", "store.go")
 
-	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/table/actor.go", "\npackage table", actorSQLBuilderFile)
+	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/table/actor.go", actorSQLBuilderFile)
 
 	// View SQL Builder files
 	viewSQLBuilderFiles, err := ioutil.ReadDir("./.gentestdata2/jetdb/dvds/view")
@@ -110,14 +110,14 @@ func assertGeneratedFiles(t *testing.T) {
 	testutils.AssertFileNamesEqual(t, viewSQLBuilderFiles, "actor_info.go", "film_list.go", "nicer_but_slower_film_list.go",
 		"sales_by_film_category.go", "customer_list.go", "sales_by_store.go", "staff_list.go")
 
-	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/view/actor_info.go", "\npackage view", actorInfoSQLBuilderFile)
+	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/view/actor_info.go", actorInfoSQLBuilderFile)
 
 	// Enums SQL Builder files
 	enumFiles, err := ioutil.ReadDir("./.gentestdata2/jetdb/dvds/enum")
 	assert.NoError(t, err)
 
 	testutils.AssertFileNamesEqual(t, enumFiles, "mpaa_rating.go")
-	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/enum/mpaa_rating.go", "\npackage enum", mpaaRatingEnumFile)
+	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/enum/mpaa_rating.go", mpaaRatingEnumFile)
 
 	// Model files
 	modelFiles, err := ioutil.ReadDir("./.gentestdata2/jetdb/dvds/model")
@@ -129,10 +129,17 @@ func assertGeneratedFiles(t *testing.T) {
 		"actor_info.go", "film_list.go", "nicer_but_slower_film_list.go", "sales_by_film_category.go",
 		"customer_list.go", "sales_by_store.go", "staff_list.go")
 
-	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/model/actor.go", "\npackage model", actorModelFile)
+	testutils.AssertFileContent(t, "./.gentestdata2/jetdb/dvds/model/actor.go", actorModelFile)
 }
 
 var mpaaRatingEnumFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package enum
 
 import "github.com/go-jet/jet/postgres"
@@ -153,6 +160,13 @@ var MpaaRating = &struct {
 `
 
 var actorSQLBuilderFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package table
 
 import (
@@ -220,6 +234,13 @@ func newActorTableImpl(schemaName, tableName string) actorTable {
 `
 
 var actorModelFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package model
 
 import (
@@ -235,6 +256,13 @@ type Actor struct {
 `
 
 var actorInfoSQLBuilderFile = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package view
 
 import (
@@ -310,8 +338,8 @@ func TestGeneratedAllTypesSQLBuilderFiles(t *testing.T) {
 	assert.NoError(t, err)
 
 	testutils.AssertFileNamesEqual(t, enumFiles, "mood.go", "level.go")
-	testutils.AssertFileContent(t, enumDir+"mood.go", "\npackage enum", moodEnumContent)
-	testutils.AssertFileContent(t, enumDir+"level.go", "\npackage enum", levelEnumContent)
+	testutils.AssertFileContent(t, enumDir+"mood.go", moodEnumContent)
+	testutils.AssertFileContent(t, enumDir+"level.go", levelEnumContent)
 
 	modelFiles, err := ioutil.ReadDir(modelDir)
 	assert.NoError(t, err)
@@ -319,7 +347,7 @@ func TestGeneratedAllTypesSQLBuilderFiles(t *testing.T) {
 	testutils.AssertFileNamesEqual(t, modelFiles, "all_types.go", "all_types_view.go", "employee.go", "link.go",
 		"mood.go", "person.go", "person_phone.go", "weird_names_table.go", "level.go", "user.go")
 
-	testutils.AssertFileContent(t, modelDir+"all_types.go", "\npackage model", allTypesModelContent)
+	testutils.AssertFileContent(t, modelDir+"all_types.go", allTypesModelContent)
 
 	tableFiles, err := ioutil.ReadDir(tableDir)
 	assert.NoError(t, err)
@@ -327,10 +355,17 @@ func TestGeneratedAllTypesSQLBuilderFiles(t *testing.T) {
 	testutils.AssertFileNamesEqual(t, tableFiles, "all_types.go", "employee.go", "link.go",
 		"person.go", "person_phone.go", "weird_names_table.go", "user.go")
 
-	testutils.AssertFileContent(t, tableDir+"all_types.go", "\npackage table", allTypesTableContent)
+	testutils.AssertFileContent(t, tableDir+"all_types.go", allTypesTableContent)
 }
 
 var moodEnumContent = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package enum
 
 import "github.com/go-jet/jet/postgres"
@@ -347,6 +382,13 @@ var Mood = &struct {
 `
 
 var levelEnumContent = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package enum
 
 import "github.com/go-jet/jet/postgres"
@@ -367,6 +409,13 @@ var Level = &struct {
 `
 
 var allTypesModelContent = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package model
 
 import (
@@ -440,6 +489,13 @@ type AllTypes struct {
 `
 
 var allTypesTableContent = `
+//
+// Code generated by go-jet DO NOT EDIT.
+//
+// WARNING: Changes to this file may cause incorrect behavior
+// and will be lost if the code is regenerated
+//
+
 package table
 
 import (