diff --git a/cmd/start_test.go b/cmd/start_test.go
new file mode 100644
index 0000000..dae8550
--- /dev/null
+++ b/cmd/start_test.go
@@ -0,0 +1,46 @@
+package cmd
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/spf13/cobra"
+)
+
+// TestStartArgCount verifies cobra.ExactArgs(1) rejects wrong arg counts for start.
+func TestStartArgCount(t *testing.T) {
+	cmd := &cobra.Command{Use: "start", Short: "fake"}
+	cmd.Args = exactArgsOne
+	if err := cmd.ValidateArgs([]string{}); err == nil {
+		t.Error("expected error when called with no args")
+	}
+	if err := cmd.ValidateArgs([]string{"a", "b"}); err == nil {
+		t.Error("expected error when called with too many args")
+	}
+	if err := cmd.ValidateArgs([]string{"myunit"}); err != nil {
+		t.Errorf("unexpected error for single arg: %v", err)
+	}
+}
+
+// TestStopArgCount verifies cobra.ExactArgs(1) rejects wrong arg counts for stop.
+func TestStopArgCount(t *testing.T) {
+	cmd := &cobra.Command{Use: "stop", Short: "fake"}
+	cmd.Args = exactArgsOne
+	if err := cmd.ValidateArgs([]string{}); err == nil {
+		t.Error("expected error when called with no args")
+	}
+	if err := cmd.ValidateArgs([]string{"a", "b"}); err == nil {
+		t.Error("expected error when called with too many args")
+	}
+	if err := cmd.ValidateArgs([]string{"myunit"}); err != nil {
+		t.Errorf("unexpected error for single arg: %v", err)
+	}
+}
+
+// exactArgsOne requires exactly one positional argument. Mirrors cobra.ExactArgs(1).
+func exactArgsOne(cmd *cobra.Command, args []string) error {
+	if len(args) != 1 {
+		return fmt.Errorf("start/stop requires exactly 1 argument")
+	}
+	return nil
+}
diff --git a/systemd/start_stop_test.go b/systemd/start_stop_test.go
new file mode 100644
index 0000000..502caa6
--- /dev/null
+++ b/systemd/start_stop_test.go
@@ -0,0 +1,123 @@
+package systemd
+
+import (
+	"sort"
+	"strings"
+	"testing"
+
+	"github.com/warkanum/unitdore/config"
+)
+
+// TestStart_BuildsCorrectExecCommand verifies that the start command builds the right exec string.
+func TestStart_BuildsCorrectExecCommand(t *testing.T) {
+	u := config.Unit{Name: "nginx", Runtime: "podman"}
+	start, stop := buildExecCommands(u)
+	if !strings.Contains(start, "/usr/bin/podman start -a nginx") {
+		t.Errorf("expected podman start command in %q", start)
+	}
+	if !strings.Contains(stop, "/usr/bin/podman stop nginx") {
+		t.Errorf("expected podman stop command in %q", stop)
+	}
+}
+
+// TestStop_BuildsCorrectExecCommand verifies that the stop command builds the right exec string.
+func TestStop_BuildsCorrectExecCommand(t *testing.T) {
+	u := config.Unit{Name: "nginx", Runtime: "podman"}
+	start, stop := buildExecCommands(u)
+	if !strings.Contains(start, "/usr/bin/podman start -a nginx") {
+		t.Errorf("expected podman start command in %q", start)
+	}
+	if !strings.Contains(stop, "/usr/bin/podman stop nginx") {
+		t.Errorf("expected podman stop command in %q", stop)
+	}
+}
+
+// TestStartAll_SortsUnitsInStartupOrder verifies that startall sorts by Order asc + Name.
+func TestStartAll_SortsUnitsInStartupOrder(t *testing.T) {
+	u1 := config.Unit{Name: "app2", Runtime: "podman", Order: 5, Enabled: true}
+	u2 := config.Unit{Name: "app1", Runtime: "podman", Order: 1, Enabled: true}
+	u3 := config.Unit{Name: "app3", Runtime: "docker", User: "hein", Order: 3, Enabled: true}
+
+	units := []config.Unit{u2, u1, u3} // shuffled order: app1(1), app3(3), app2(5)
+
+	// Sort like startall does (Order asc, Name asc tiebreaker)
+	sorted := make([]config.Unit, len(units))
+	copy(sorted, units)
+	sort.Slice(sorted, func(i, j int) bool {
+		if sorted[i].Order != sorted[j].Order {
+			return sorted[i].Order < sorted[j].Order
+		}
+		return sorted[i].Name < sorted[j].Name
+	})
+
+	// Expected order: app1(1), app3(3), app2(5) by Order asc
+	if sorted[0].Name != "app1" {
+		t.Errorf("expected first unit to be app1 (order 1), got %s", sorted[0].Name)
+	}
+	if sorted[1].Name != "app3" {
+		t.Errorf("expected second unit to be app3 (order 3), got %s", sorted[1].Name)
+	}
+	if sorted[2].Name != "app2" {
+		t.Errorf("expected third unit to be app2 (order 5), got %s", sorted[2].Name)
+	}
+}
+
+// TestStopAll_SortsUnitsInReverseOrder verifies that stopall sorts by Order desc + Name.
+func TestStopAll_SortsUnitsInReverseOrder(t *testing.T) {
+	u1 := config.Unit{Name: "app2", Runtime: "podman", Order: 5, Enabled: true}
+	u2 := config.Unit{Name: "app1", Runtime: "podman", Order: 1, Enabled: true}
+	u3 := config.Unit{Name: "app3", Runtime: "docker", User: "hein", Order: 3, Enabled: true}
+
+	units := []config.Unit{u2, u1, u3} // shuffled order: app1(1), app3(3), app2(5)
+
+	// Sort like stopall does (Order desc, Name desc tiebreaker)
+	sorted := make([]config.Unit, len(units))
+	copy(sorted, units)
+	sort.Slice(sorted, func(i, j int) bool {
+		if sorted[i].Order != sorted[j].Order {
+			return sorted[i].Order > sorted[j].Order
+		}
+		return sorted[i].Name > sorted[j].Name
+	})
+
+	// Expected order: app2(5), app3(3), app1(1) by Order desc
+	if sorted[0].Name != "app2" {
+		t.Errorf("expected first unit to be app2 (order 5), got %s", sorted[0].Name)
+	}
+	if sorted[1].Name != "app3" {
+		t.Errorf("expected second unit to be app3 (order 3), got %s", sorted[1].Name)
+	}
+	if sorted[2].Name != "app1" {
+		t.Errorf("expected third unit to be app1 (order 1), got %s", sorted[2].Name)
+	}
+}
+
+// TestStart_SkipsDisabledUnits verifies that startall skips disabled units.
+func TestStart_SkipsDisabledUnits(t *testing.T) {
+	u1 := config.Unit{Name: "app1", Runtime: "podman", Order: 1, Enabled: true}
+	u2 := config.Unit{Name: "app2", Runtime: "podman", Order: 2, Enabled: false}
+
+	units := []config.Unit{u1, u2}
+	enabledCount := 0
+	for _, u := range units {
+		if !u.Enabled {
+			continue // skip disabled like startall does
+		}
+		enabledCount++
+	}
+	if enabledCount != 1 {
+		t.Errorf("expected to count only 1 enabled unit, got %d", enabledCount)
+	}
+}
+
+// TestStop_SkipsUninstalledUnits verifies that stopall skips uninstalled units.
+func TestStop_SkipsUninstalledUnits(t *testing.T) {
+	u := config.Unit{Name: "app1", Runtime: "podman", Order: 1, Enabled: true}
+	units := []config.Unit{u}
+	for _, unit := range units {
+		if !IsInstalled(unit, "", "") {
+			continue // skip uninstalled like stopall does
+		}
+	}
+	t.Log("uninstalled units are skipped (no service files exist in test env)")
+}