Rendering: Add light theme for errors (#41616)

* Add light theme for error rendering

* Fix lint

* Update images and add rendering_limit_x images

pkg/services/rendering/rendering_test.go

@@ -1,9 +1,13 @@
 package rendering
 
 import (
+	"context"
+	"errors"
+	"path/filepath"
 	"testing"
 
 	"github.com/grafana/grafana/pkg/setting"
+	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -58,3 +62,80 @@ func TestGetUrl(t *testing.T) {
 		})
 	})
 }
+
+func TestRenderErrorImage(t *testing.T) {
+	path, err := filepath.Abs("../../../")
+	require.NoError(t, err)
+
+	rs := RenderingService{
+		Cfg: &setting.Cfg{
+			HomePath: path,
+		},
+	}
+	t.Run("No theme set returns error image with dark theme", func(t *testing.T) {
+		result, err := rs.RenderErrorImage("", nil)
+		require.NoError(t, err)
+		assert.Equal(t, result.FilePath, path+"/public/img/rendering_error_dark.png")
+	})
+
+	t.Run("Timeout error returns timeout error image", func(t *testing.T) {
+		result, err := rs.RenderErrorImage(ThemeLight, ErrTimeout)
+		require.NoError(t, err)
+		assert.Equal(t, result.FilePath, path+"/public/img/rendering_timeout_light.png")
+	})
+
+	t.Run("Generic error returns error image", func(t *testing.T) {
+		result, err := rs.RenderErrorImage(ThemeLight, errors.New("an error"))
+		require.NoError(t, err)
+		assert.Equal(t, result.FilePath, path+"/public/img/rendering_error_light.png")
+	})
+
+	t.Run("Unknown image path returns error", func(t *testing.T) {
+		result, err := rs.RenderErrorImage("abc", errors.New("random error"))
+		assert.Error(t, err)
+		assert.Nil(t, result)
+	})
+}
+
+func TestRenderLimitImage(t *testing.T) {
+	path, err := filepath.Abs("../../../")
+	require.NoError(t, err)
+
+	rs := RenderingService{
+		Cfg: &setting.Cfg{
+			HomePath: path,
+		},
+		inProgressCount: 2,
+	}
+
+	tests := []struct {
+		name     string
+		theme    Theme
+		expected string
+	}{
+		{
+			name:     "Light theme returns light image",
+			theme:    ThemeLight,
+			expected: path + "/public/img/rendering_limit_light.png",
+		},
+		{
+			name:     "Dark theme returns dark image",
+			theme:    ThemeDark,
+			expected: path + "/public/img/rendering_limit_dark.png",
+		},
+		{
+			name:     "No theme returns dark image",
+			theme:    "",
+			expected: path + "/public/img/rendering_limit_dark.png",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			opts := Opts{Theme: tc.theme, ConcurrentLimit: 1}
+			result, err := rs.Render(context.Background(), opts)
+			assert.NoError(t, err)
+			assert.Equal(t, tc.expected, result.FilePath)
+		})
+	}
+}