feat(render): experimental package to render arbitrary values to different formats

multi_test.go

@@ -0,0 +1,110 @@
+package render_test
+
+import (
+	"bytes"
+	"errors"
+	"testing"
+
+	"github.com/jimeh/go-render"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMultiRenderer_Render(t *testing.T) {
+	successRenderer := &mockRenderer{output: "success output"}
+	cannotRenderer := &mockRenderer{err: render.ErrCannotRender}
+	failRenderer := &mockRenderer{err: errors.New("mock error")}
+
+	tests := []struct {
+		name      string
+		renderers []render.Renderer
+		value     interface{}
+		want      string
+		wantErr   string
+		wantErrIs []error
+	}{
+		{
+			name: "no renderer can render",
+			renderers: []render.Renderer{
+				cannotRenderer,
+				cannotRenderer,
+			},
+			value:     struct{}{},
+			wantErrIs: []error{render.ErrCannotRender},
+		},
+		{
+			name: "one renderer can render",
+			renderers: []render.Renderer{
+				cannotRenderer,
+				successRenderer,
+				cannotRenderer,
+			},
+			value: struct{}{},
+			want:  "success output",
+		},
+		{
+			name: "multiple renderers can render",
+			renderers: []render.Renderer{
+				&mockRenderer{err: render.ErrCannotRender},
+				&mockRenderer{output: "first output"},
+				&mockRenderer{output: "second output"},
+			},
+			value: struct{}{},
+			want:  "first output",
+		},
+		{
+			name: "first renderer fails",
+			renderers: []render.Renderer{
+				failRenderer,
+				successRenderer,
+			},
+			value:   struct{}{},
+			wantErr: "mock error",
+		},
+		{
+			name: "fails after cannot render",
+			renderers: []render.Renderer{
+				cannotRenderer,
+				failRenderer,
+				successRenderer,
+			},
+			value:   struct{}{},
+			wantErr: "mock error",
+		},
+		{
+			name: "fails after success render",
+			renderers: []render.Renderer{
+				successRenderer,
+				failRenderer,
+				cannotRenderer,
+			},
+			value: struct{}{},
+			want:  "success output",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			mr := &render.MultiRenderer{
+				Renderers: tt.renderers,
+			}
+
+			var buf bytes.Buffer
+			err := mr.Render(&buf, tt.value)
+			got := buf.String()
+
+			if tt.wantErr != "" {
+				require.Error(t, err)
+				assert.EqualError(t, err, tt.wantErr)
+			}
+			for _, e := range tt.wantErrIs {
+				assert.ErrorIs(t, err, e)
+			}
+
+			if tt.wantErr == "" && len(tt.wantErrIs) == 0 {
+				require.NoError(t, err)
+				assert.Equal(t, tt.want, got)
+			}
+		})
+	}
+}