Plugins: Update renderer plugin source (#80643)

* rework renderer plugin source

* add tests

pkg/services/pluginsintegration/renderer/renderer_test.go

@@ -0,0 +1,82 @@
+package renderer
+
+import (
+	"context"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/grafana/grafana/pkg/plugins"
+	"github.com/grafana/grafana/pkg/plugins/config"
+	"github.com/grafana/grafana/pkg/plugins/manager/fakes"
+)
+
+func TestRenderer(t *testing.T) {
+	t.Run("Test Renderer will treat directories under plugins path as individual sources", func(t *testing.T) {
+		testdataDir := filepath.Join("testdata", "plugins")
+
+		numLoaded := 0
+		numUnloaded := 0
+		loader := &fakes.FakeLoader{
+			LoadFunc: func(ctx context.Context, src plugins.PluginSource) ([]*plugins.Plugin, error) {
+				require.True(t, src.PluginClass(ctx) == plugins.ClassExternal)
+				require.Len(t, src.PluginURIs(ctx), 1)
+				require.True(t, strings.HasPrefix(src.PluginURIs(ctx)[0], testdataDir))
+
+				numLoaded++
+				return []*plugins.Plugin{}, nil
+			},
+			UnloadFunc: func(_ context.Context, _ *plugins.Plugin) (*plugins.Plugin, error) {
+				numUnloaded++
+				return nil, nil
+			},
+		}
+		cfg := &config.Cfg{
+			PluginsPath: filepath.Join(testdataDir),
+		}
+
+		m := NewManager(cfg, loader)
+
+		r, exists := m.Renderer(context.Background())
+		require.False(t, exists)
+		require.Equal(t, 4, numLoaded)
+		require.Equal(t, 0, numUnloaded)
+		require.Nil(t, r)
+	})
+
+	t.Run("Test Renderer load all directories until a plugin is returned", func(t *testing.T) {
+		testdataDir := filepath.Join("testdata", "plugins")
+
+		numLoaded := 0
+		numUnloaded := 0
+		p := &plugins.Plugin{
+			JSONData: plugins.JSONData{ID: "test"},
+		}
+		loader := &fakes.FakeLoader{
+			LoadFunc: func(ctx context.Context, src plugins.PluginSource) ([]*plugins.Plugin, error) {
+				numLoaded++
+				if strings.HasPrefix(src.PluginURIs(ctx)[0], filepath.Join(testdataDir, "renderer")) {
+					return []*plugins.Plugin{p}, nil
+				}
+				return []*plugins.Plugin{}, nil
+			},
+			UnloadFunc: func(_ context.Context, _ *plugins.Plugin) (*plugins.Plugin, error) {
+				numUnloaded++
+				return nil, nil
+			},
+		}
+		cfg := &config.Cfg{
+			PluginsPath: filepath.Join(testdataDir),
+		}
+
+		m := NewManager(cfg, loader)
+
+		r, exists := m.Renderer(context.Background())
+		require.True(t, exists)
+		require.Equal(t, 3, numLoaded)
+		require.Equal(t, 0, numUnloaded)
+		require.NotNil(t, r)
+	})
+}