video backend CLI flag

cmd/mxl-pattern/main_test.go

@@ -9,6 +9,7 @@ import (
 
 	"mxl-pattern-generator/internal/audio"
 	"mxl-pattern-generator/internal/flowdef"
+	"mxl-pattern-generator/internal/video"
 )
 
 func TestParseArgsHelpStopsBeforeValidation(t *testing.T) {
@@ -112,6 +113,46 @@ func TestValidateVideoArgsSkipsDisabledVideo(t *testing.T) {
 	}
 }
 
+func TestParseVideoBackend(t *testing.T) {
+	tests := []struct {
+		name    string
+		value   string
+		want    video.Backend
+		wantErr bool
+	}{
+		{name: "zero value defaults to auto", want: video.BackendAuto},
+		{name: "auto", value: "auto", want: video.BackendAuto},
+		{name: "gpu", value: "gpu", want: video.BackendGPU},
+		{name: "cpu", value: "cpu", want: video.BackendCPU},
+		{name: "unknown", value: "other", wantErr: true},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			got, err := parseVideoBackend(tc.value)
+			if tc.wantErr {
+				if err == nil || !strings.Contains(err.Error(), "unsupported video backend") {
+					t.Fatalf("error = %v, want unsupported backend error", err)
+				}
+				return
+			}
+			if err != nil {
+				t.Fatalf("parseVideoBackend: %v", err)
+			}
+			if got != tc.want {
+				t.Fatalf("backend = %q, want %q", got, tc.want)
+			}
+		})
+	}
+}
+
+func TestValidateVideoArgsRejectsUnknownBackend(t *testing.T) {
+	args := appArgs{videoBackend: "other"}
+	if err := validateVideoArgs(&args); err == nil || !strings.Contains(err.Error(), "unsupported video backend") {
+		t.Fatalf("error = %v, want unsupported backend error", err)
+	}
+}
+
 func TestValidateMediaSelection(t *testing.T) {
 	tests := []struct {
 		name       string
@@ -187,6 +228,30 @@ func TestBuildVideoConfigFromArgs(t *testing.T) {
 	if cfg.Rate().Num != 30000 || cfg.Rate().Den != 1001 {
 		t.Fatalf("rate = %d/%d, want 30000/1001", cfg.Rate().Num, cfg.Rate().Den)
 	}
+	if cfg.Backend != video.BackendAuto {
+		t.Fatalf("backend = %q, want %q", cfg.Backend, video.BackendAuto)
+	}
+}
+
+func TestBuildVideoConfigBackends(t *testing.T) {
+	for _, backend := range []video.Backend{video.BackendGPU, video.BackendCPU} {
+		t.Run(string(backend), func(t *testing.T) {
+			cfg, err := buildVideoConfig(appArgs{
+				videoUUID:    "5fbec3b1-1b0f-417d-9059-8b94a47197ed",
+				videoWidth:   1920,
+				videoHeight:  1080,
+				videoFPS:     "25",
+				pattern:      "ebu75",
+				videoBackend: string(backend),
+			})
+			if err != nil {
+				t.Fatalf("buildVideoConfig: %v", err)
+			}
+			if cfg.Backend != backend {
+				t.Fatalf("backend = %q, want %q", cfg.Backend, backend)
+			}
+		})
+	}
 }
 
 func TestBuildVideoConfigDisabled(t *testing.T) {