diff --git a/app/app_test.go b/app/app_test.go
new file mode 100644
index 0000000..5949cd5
--- /dev/null
+++ b/app/app_test.go
@@ -0,0 +1,30 @@
+package app
+
+import (
+	_ "github.com/go-sql-driver/mysql"
+	"gitnet.fr/deblan/database-anonymizer/config"
+	"gitnet.fr/deblan/database-anonymizer/faker"
+	"testing"
+)
+
+func GetApp() App {
+	return App{
+		FakeManager: faker.NewFakeManager(),
+		DbConfig:    config.DatabaseConfig{Type: "mysql", Dsn: "mysql://foo:bar@tests"},
+	}
+}
+
+func TestAppCreateSelectQuery(t *testing.T) {
+	c := config.SchemaConfigAction{Table: "foo"}
+	app := GetApp()
+
+	if app.CreateSelectQuery(c) != "SELECT * FROM `foo`" {
+		t.Fatalf("TestAppCreateSelectQuery: empty configured query check failed")
+	}
+
+	c = config.SchemaConfigAction{Table: "foo", Query: "query"}
+
+	if app.CreateSelectQuery(c) != "query" {
+		t.Fatalf("TestAppCreateSelectQuery: configured query check failed")
+	}
+}
diff --git a/data/data_test.go b/data/data_test.go
new file mode 100644
index 0000000..560574a
--- /dev/null
+++ b/data/data_test.go
@@ -0,0 +1,88 @@
+package data
+
+import (
+	"gitnet.fr/deblan/database-anonymizer/faker"
+	"testing"
+)
+
+func TestDataFroms(t *testing.T) {
+	d := Data{}
+
+	var varInt64 int64
+	varInt64 = 42
+	d.FromInt64(varInt64)
+	if d.Value != "42" {
+		t.Fatalf("TestDataFroms: FromInt64 check failed")
+	}
+
+	v := []byte{'A', 'B', 'C'}
+
+	d.FromByte(v)
+
+	if d.Value != "ABC" {
+		t.Fatalf("TestDataFroms: FromByte check failed")
+	}
+}
+
+func TestDataIsTwigExpression(t *testing.T) {
+	d := Data{Faker: "foo"}
+	if d.IsTwigExpression() {
+		t.Fatalf("IsTwigExpression: IsTwigExpression check failed")
+	}
+
+	d = Data{Faker: "foo {{"}
+	if !d.IsTwigExpression() {
+		t.Fatalf("IsTwigExpression: IsTwigExpression check failed")
+	}
+
+	d = Data{Faker: "}}"}
+	if !d.IsTwigExpression() {
+		t.Fatalf("IsTwigExpression: IsTwigExpression check failed")
+	}
+}
+
+func TestDataUpdate(t *testing.T) {
+	row := make(map[string]Data)
+	row["bar"] = Data{Value: "bar_value"}
+	manager := faker.NewFakeManager()
+
+	d := Data{Faker: "", Value: "foo"}
+	if d.IsUpdated {
+		t.Fatalf("TestDataUpdate: IsUpdated  check failed")
+	}
+
+	d.Update(row, manager)
+	if d.IsUpdated {
+		t.Fatalf("TestDataUpdate: IsUpdated  check failed")
+	}
+	if d.Value != "foo" {
+		t.Fatalf("TestDataUpdate: Value check failed")
+	}
+
+	d = Data{Faker: "_", Value: "foo"}
+	d.Update(row, manager)
+	if d.IsUpdated {
+		t.Fatalf("TestDataUpdate: IsUpdated  check failed")
+	}
+	if d.Value != "foo" {
+		t.Fatalf("TestDataUpdate: Value check failed")
+	}
+
+	d = Data{Faker: "address", Value: "foo"}
+	d.Update(row, manager)
+	if !d.IsUpdated {
+		t.Fatalf("TestDataUpdate: IsUpdated  check failed")
+	}
+	if d.Value == "foo" && len(d.Value) > 0 {
+		t.Fatalf("TestDataUpdate: Value check failed")
+	}
+
+	d = Data{Faker: "Twig {{ bar }}", Value: "foo"}
+	d.Update(row, manager)
+	if !d.IsUpdated {
+		t.Fatalf("TestDataUpdate: IsUpdated  check failed")
+	}
+	if d.Value != "Twig bar_value" {
+		t.Fatalf("TestDataUpdate: Value check failed")
+	}
+}