diff --git a/internal/app/ship_test.go b/internal/app/ship_test.go
new file mode 100644
index 0000000..bc6f90b
--- /dev/null
+++ b/internal/app/ship_test.go
@@ -0,0 +1,62 @@
+package app
+
+import (
+	"os/exec"
+	"testing"
+)
+
+func TestScpArgs(t *testing.T) {
+	args := scpArgs([]string{"/out/a.mp3", "/out/b.mp3", "/out/playlist.m3u8"},
+		"root@vps:/opt/icecast/web/ai-radio/", "")
+	joined := ""
+	for _, a := range args {
+		joined += a + " "
+	}
+	for _, want := range []string{
+		"-o StrictHostKeyChecking=accept-new",
+		"/out/a.mp3",
+		"/out/b.mp3",
+		"/out/playlist.m3u8",
+		"root@vps:/opt/icecast/web/ai-radio/",
+	} {
+		if !contains(joined, want) {
+			t.Fatalf("scp args missing %q: %s", want, joined)
+		}
+	}
+	// playlist must be last so links resolve before the list appears
+	last := args[len(args)-1]
+	if last != "root@vps:/opt/icecast/web/ai-radio/" {
+		t.Fatal("target must be last arg")
+	}
+	// playlist before target, after mp3s
+	pi := -1
+	for i, a := range args {
+		if a == "/out/playlist.m3u8" {
+			pi = i
+		}
+	}
+	if pi < 2 {
+		t.Fatal("playlist should come after the mp3s")
+	}
+}
+
+func TestScpArgsWithKey(t *testing.T) {
+	args := scpArgs([]string{"/x.mp3"}, "u@h:/d/", "/keys/id")
+	found := false
+	for i, a := range args {
+		if a == "-i" && i+1 < len(args) && args[i+1] == "/keys/id" {
+			found = true
+		}
+	}
+	if !found {
+		t.Fatalf("identity file not passed: %v", args)
+	}
+}
+
+func TestScpEmptyNoop(t *testing.T) {
+	if err := Ship(nil, "u@h:/d/", ""); err != nil {
+		t.Fatalf("empty ship should be a no-op, got %v", err)
+	}
+}
+
+var _ = exec.Command // keep import if unused in future edits