diff --git a/metadapta_test.go b/metadapta_test.go
new file mode 100644
index 0000000..c4c8f9b
--- /dev/null
+++ b/metadapta_test.go
@@ -0,0 +1,27 @@
+package hopp
+
+import "bytes"
+import "slices"
+import "testing"
+
+func TestDecodeMessageA(test *testing.T) {
+	transID, method, payload, err := decodeMessageA(bytes.NewReader([]byte {
+		0x58, 0x00, 0xFE, 0xAB, 0xC3, 0x10, 0x4F, 0x04,
+		0x6B, 0x12,
+		0x00, 0x06,
+		0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
+	}))
+	if err != nil {
+		test.Fatal(err)
+	}
+	if got, correct := transID, int64(0x5800FEABC3104F04); got != correct {
+		test.Fatalf("not equal: %v %v", got, correct)
+	}
+	if got, correct := method, uint16(0x6B12); got != correct {
+		test.Fatalf("not equal: %v %v", got, correct)
+	}
+	correctPayload := []byte { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05 }
+	if got, correct := payload, correctPayload; !slices.Equal(got, correct) {
+		test.Fatalf("not equal: %v %v", got, correct)
+	}
+}
diff --git a/tape/types_test.go b/tape/types_test.go
index 71d938c..994a586 100644
--- a/tape/types_test.go
+++ b/tape/types_test.go
@@ -246,6 +246,23 @@ func TestStringArray(test *testing.T) {
 	}
 }
 
+func TestU16CastSafe(test *testing.T) {
+	number, ok := U16CastSafe(90_000)
+	if ok { test.Fatalf("false positive: %v, %v", number, ok) }
+	number, ok = U16CastSafe(-478)
+	if ok { test.Fatalf("false positive: %v, %v", number, ok) }
+	number, ok = U16CastSafe(3870)
+	if !ok { test.Fatalf("false negative: %v, %v", number, ok) }
+	if got, correct := number, uint16(3870); got != correct {
+		test.Fatalf("not equal: %v %v", got, correct)
+	}
+	number, ok = U16CastSafe(0)
+	if !ok { test.Fatalf("false negative: %v, %v", number, ok) }
+	if got, correct := number, uint16(0); got != correct {
+		test.Fatalf("not equal: %v %v", got, correct)
+	}
+}
+
 func randString(length int) string {
 	buffer := make([]byte, length)
 	for index := range buffer {