chore: 并入 iotlcm-upstream-chan 历史到 upstream-chan/（原提交 1e74497）

upstream-chan/internal/logic/upstreamimpl/dx/sign_test.go

@@ -0,0 +1,15 @@
+package dx
+
+import "testing"
+
+func TestV3SignatureKeepsLegacyEncodingAndUsesUppercase(t *testing.T) {
+	// MD5("abc") is 900150983cd24fb0d6963f7d28e17f72.
+	legacy, err := BuildSign("", "abc", "", "")
+	if err != nil || legacy != "3930303135303938336364323466623064363936336637643238653137663732" {
+		t.Fatalf("legacy signature: %s, %v", legacy, err)
+	}
+	v3, err := BuildSignV3("", "abc", "", "")
+	if err != nil || v3 != "3930303135303938336364323466623064363936336637643238653137663732" {
+		t.Fatalf("v3 signature: %s, %v", v3, err)
+	}
+}