tpl/collections: Improve type handling in collections.Slice

Fixes #5188

hugolib/collections_test.go

@@ -0,0 +1,88 @@
+// Copyright 2018 The Hugo Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package hugolib
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestGroupFunc(t *testing.T) {
+	assert := require.New(t)
+
+	pageContent := `
+---
+title: "Page"
+---
+
+`
+	b := newTestSitesBuilder(t)
+	b.WithSimpleConfigFile().
+		WithContent("page1.md", pageContent, "page2.md", pageContent).
+		WithTemplatesAdded("index.html", `
+{{ $cool := .Site.RegularPages | group "cool" }}
+{{ $cool.Key }}: {{ len $cool.Pages }}
+
+`)
+	b.CreateSites().Build(BuildCfg{})
+
+	assert.Equal(1, len(b.H.Sites))
+	require.Len(t, b.H.Sites[0].RegularPages, 2)
+
+	b.AssertFileContent("public/index.html", "cool: 2")
+}
+
+func TestSliceFunc(t *testing.T) {
+	assert := require.New(t)
+
+	pageContent := `
+---
+title: "Page"
+tags: ["blue", "green"]
+tags_weight: %d
+---
+
+`
+	b := newTestSitesBuilder(t)
+	b.WithSimpleConfigFile().
+		WithContent("page1.md", fmt.Sprintf(pageContent, 10), "page2.md", fmt.Sprintf(pageContent, 20)).
+		WithTemplatesAdded("index.html", `
+{{ $cool := first 1 .Site.RegularPages | group "cool" }}
+{{ $blue := after 1 .Site.RegularPages | group "blue" }}
+{{ $weightedPages := index (index .Site.Taxonomies "tags") "blue" }}
+
+{{ $p1 := index .Site.RegularPages 0 }}{{ $p2 := index .Site.RegularPages 1 }}
+{{ $wp1 := index $weightedPages 0 }}{{ $wp2 := index $weightedPages 1 }}
+
+{{ $pages := slice $p1 $p2 }}
+{{ $pageGroups := slice $cool $blue }}
+{{ $weighted := slice $wp1 $wp2 }}
+
+{{ printf "pages:%d:%T:%v/%v" (len $pages) $pages (index $pages 0) (index $pages 1) }}
+{{ printf "pageGroups:%d:%T:%v/%v" (len $pageGroups) $pageGroups (index (index $pageGroups 0).Pages 0) (index (index $pageGroups 1).Pages 0)}}
+{{ printf "weightedPages:%d::%T:%v" (len $weighted) $weighted $weighted | safeHTML }}
+
+`)
+	b.CreateSites().Build(BuildCfg{})
+
+	assert.Equal(1, len(b.H.Sites))
+	require.Len(t, b.H.Sites[0].RegularPages, 2)
+
+	b.AssertFileContent("public/index.html",
+		"pages:2:hugolib.Pages:Page(/page1.md)/Page(/page2.md)",
+		"pageGroups:2:hugolib.PagesGroup:Page(/page1.md)/Page(/page2.md)",
+		`weightedPages:2::hugolib.WeightedPages:[WeightedPage(10,"Page") WeightedPage(20,"Page")]`)
+}