feat(theming): apply writes four tool configs to $HOME

internal/theming/theming_test.go

@@ -1,7 +1,12 @@
 package theming
 
 import (
+	"os"
+	"path/filepath"
+	"strings"
 	"testing"
+
+	"github.com/MDietermann/ArduinoArchSetup/internal/config"
 )
 
 func TestListDiscoversThemes(t *testing.T) {
@@ -40,3 +45,37 @@ func TestListIsSortedByID(t *testing.T) {
 		}
 	}
 }
+
+func TestApplyWritesFourToolConfigs(t *testing.T) {
+	home := t.TempDir()
+	t.Setenv("HOME", home)
+	if err := Apply(config.Config{}, "gruvbox"); err != nil {
+		t.Fatal(err)
+	}
+
+	checks := []struct{ rel, wantPrefix string }{
+		{".config/starship.toml", "palette"},
+		{".config/zellij/config.kdl", "theme"},
+		{".config/yazi/theme.toml", ""},
+		{".config/lazygit/config.yml", "gui"},
+	}
+	for _, c := range checks {
+		data, err := os.ReadFile(filepath.Join(home, c.rel))
+		if err != nil {
+			t.Errorf("%s missing: %v", c.rel, err)
+			continue
+		}
+		if len(data) == 0 {
+			t.Errorf("%s empty", c.rel)
+		}
+		if c.wantPrefix != "" && !strings.HasPrefix(strings.TrimSpace(string(data)), c.wantPrefix) {
+			t.Errorf("%s: want prefix %q, got %q", c.rel, c.wantPrefix, string(data[:min(len(data), 40)]))
+		}
+	}
+}
+
+func TestApplyUnknownThemeErrors(t *testing.T) {
+	if err := Apply(config.Config{}, "does-not-exist"); err == nil {
+		t.Fatal("want error on unknown theme")
+	}
+}