diff --git a/lib/sfregexp/regexp_test.go b/lib/sfregexp/regexp_test.go
new file mode 100644
index 000000000..af1e6d974
--- /dev/null
+++ b/lib/sfregexp/regexp_test.go
@@ -0,0 +1,25 @@
+package sfregexp
+
+import (
+	"testing"
+)
+
+func TestValidSiret(t *testing.T) {
+	type args struct {
+		siret string
+	}
+	tests := []struct {
+		name string
+		args args
+		want bool
+	}{
+		{"cas normal", args{"33516816700021"}, true},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ValidSiret(tt.args.siret); got != tt.want {
+				t.Errorf("ValidSiret() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}