diff --git a/cmd/picoclaw-launcher-tui/internal/ui/gateway_posix.go b/cmd/picoclaw-launcher-tui/internal/ui/gateway_posix.go
index bc874f7f2..143e5558a 100644
--- a/cmd/picoclaw-launcher-tui/internal/ui/gateway_posix.go
+++ b/cmd/picoclaw-launcher-tui/internal/ui/gateway_posix.go
@@ -5,12 +5,14 @@ package ui
 
 import "os/exec"
 
+var execCommand = exec.Command
+
 func isGatewayProcessRunning() bool {
-	cmd := exec.Command("sh", "-c", "pgrep -f 'picoclaw\\s+gateway' >/dev/null 2>&1")
+	cmd := execCommand("sh", "-c", "pgrep -f 'picoclaw\\s+gateway' >/dev/null 2>&1")
 	return cmd.Run() == nil
 }
 
 func stopGatewayProcess() error {
-	cmd := exec.Command("sh", "-c", "pkill -f 'picoclaw\\s+gateway' >/dev/null 2>&1")
+	cmd := execCommand("sh", "-c", "pkill -f 'picoclaw\\s+gateway' >/dev/null 2>&1")
 	return cmd.Run()
 }
diff --git a/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows.go b/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows.go
index 7067a5c13..8b4c12096 100644
--- a/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows.go
+++ b/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows.go
@@ -5,12 +5,14 @@ package ui
 
 import "os/exec"
 
+var execCommand = exec.Command
+
 func isGatewayProcessRunning() bool {
-	cmd := exec.Command("tasklist", "/FI", "IMAGENAME eq picoclaw.exe")
+	cmd := execCommand("tasklist", "/FI", "IMAGENAME eq picoclaw.exe")
 	return cmd.Run() == nil
 }
 
 func stopGatewayProcess() error {
-	cmd := exec.Command("taskkill", "/F", "/IM", "picoclaw.exe")
+	cmd := execCommand("taskkill", "/F", "/IM", "picoclaw.exe")
 	return cmd.Run()
 }
diff --git a/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows_test.go b/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows_test.go
new file mode 100644
index 000000000..645ae602b
--- /dev/null
+++ b/cmd/picoclaw-launcher-tui/internal/ui/gateway_windows_test.go
@@ -0,0 +1,131 @@
+//go:build windows
+// +build windows
+
+package ui
+
+import (
+	"os"
+	"os/exec"
+	"reflect"
+	"strconv"
+	"testing"
+)
+
+func TestIsGatewayProcessRunning(t *testing.T) {
+	origExecCommand := execCommand
+	defer func() { execCommand = origExecCommand }()
+
+	tests := []struct {
+		name       string
+		exitCode   int
+		wantResult bool
+	}{
+		{
+			name:       "running",
+			exitCode:   0,
+			wantResult: true,
+		},
+		{
+			name:       "not running",
+			exitCode:   1,
+			wantResult: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var gotName string
+			var gotArgs []string
+
+			execCommand = func(name string, args ...string) *exec.Cmd {
+				gotName = name
+				gotArgs = args
+
+				cmd := exec.Command(os.Args[0], "-test.run=TestHelperProcess", "--")
+				cmd.Env = append(os.Environ(),
+					"GO_WANT_HELPER_PROCESS=1",
+					"GO_WANT_HELPER_PROCESS_EXIT_CODE="+strconv.Itoa(tt.exitCode),
+				)
+				return cmd
+			}
+
+			got := isGatewayProcessRunning()
+			if got != tt.wantResult {
+				t.Errorf("isGatewayProcessRunning() = %v, want %v", got, tt.wantResult)
+			}
+			if gotName != "tasklist" {
+				t.Errorf("expected command name tasklist, got %s", gotName)
+			}
+			expectedArgs := []string{"/FI", "IMAGENAME eq picoclaw.exe"}
+			if !reflect.DeepEqual(gotArgs, expectedArgs) {
+				t.Errorf("expected args %v, got %v", expectedArgs, gotArgs)
+			}
+		})
+	}
+}
+
+func TestStopGatewayProcess(t *testing.T) {
+	origExecCommand := execCommand
+	defer func() { execCommand = origExecCommand }()
+
+	tests := []struct {
+		name     string
+		exitCode int
+		wantErr  bool
+	}{
+		{
+			name:     "success",
+			exitCode: 0,
+			wantErr:  false,
+		},
+		{
+			name:     "failure",
+			exitCode: 1,
+			wantErr:  true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var gotName string
+			var gotArgs []string
+
+			execCommand = func(name string, args ...string) *exec.Cmd {
+				gotName = name
+				gotArgs = args
+
+				cmd := exec.Command(os.Args[0], "-test.run=TestHelperProcess", "--")
+				cmd.Env = append(os.Environ(),
+					"GO_WANT_HELPER_PROCESS=1",
+					"GO_WANT_HELPER_PROCESS_EXIT_CODE="+strconv.Itoa(tt.exitCode),
+				)
+				return cmd
+			}
+
+			err := stopGatewayProcess()
+			if (err != nil) != tt.wantErr {
+				t.Errorf("stopGatewayProcess() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if gotName != "taskkill" {
+				t.Errorf("expected command name taskkill, got %s", gotName)
+			}
+			expectedArgs := []string{"/F", "/IM", "picoclaw.exe"}
+			if !reflect.DeepEqual(gotArgs, expectedArgs) {
+				t.Errorf("expected args %v, got %v", expectedArgs, gotArgs)
+			}
+		})
+	}
+}
+
+func TestHelperProcess(t *testing.T) {
+	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+		return
+	}
+	defer os.Exit(0)
+
+	if code := os.Getenv("GO_WANT_HELPER_PROCESS_EXIT_CODE"); code != "" {
+		c, _ := strconv.Atoi(code)
+		os.Exit(c)
+	}
+	os.Exit(0)
+}