Add multilingual multihost support

This commit adds multihost support when more than one language is configured and `baseURL` is set per language.

Updates #4027

hugolib/hugo_sites_multihost_test.go

@@ -0,0 +1,72 @@
+package hugolib
+
+import (
+	"testing"
+
+	"github.com/spf13/afero"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMultihosts(t *testing.T) {
+	t.Parallel()
+
+	var multiSiteTOMLConfigTemplate = `
+paginate = 1
+disablePathToLower = true
+defaultContentLanguage = "{{ .DefaultContentLanguage }}"
+defaultContentLanguageInSubdir = {{ .DefaultContentLanguageInSubdir }}
+
+[permalinks]
+other = "/somewhere/else/:filename"
+
+[Taxonomies]
+tag = "tags"
+
+[Languages]
+[Languages.en]
+baseURL = "https://example.com"
+weight = 10
+title = "In English"
+languageName = "English"
+
+[Languages.fr]
+baseURL = "https://example.fr"
+weight = 20
+title = "Le Français"
+languageName = "Français"
+
+[Languages.nn]
+baseURL = "https://example.no"
+weight = 30
+title = "På nynorsk"
+languageName = "Nynorsk"
+
+`
+
+	siteConfig := testSiteConfig{Fs: afero.NewMemMapFs(), DefaultContentLanguage: "fr", DefaultContentLanguageInSubdir: false}
+	sites := createMultiTestSites(t, siteConfig, multiSiteTOMLConfigTemplate)
+	fs := sites.Fs
+	cfg := BuildCfg{Watching: true}
+	th := testHelper{sites.Cfg, fs, t}
+	assert := require.New(t)
+
+	err := sites.Build(cfg)
+	assert.NoError(err)
+
+	th.assertFileContent("public/en/sect/doc1-slug/index.html", "Hello")
+
+	s1 := sites.Sites[0]
+
+	s1h := s1.getPage(KindHome)
+	assert.True(s1h.IsTranslated())
+	assert.Len(s1h.Translations(), 2)
+	assert.Equal("https://example.com/", s1h.Permalink())
+
+	s2 := sites.Sites[1]
+	s2h := s2.getPage(KindHome)
+	assert.Equal("https://example.fr/", s2h.Permalink())
+
+	th.assertFileContentStraight("public/fr/index.html", "French Home Page")
+	th.assertFileContentStraight("public/en/index.html", "Default Home Page")
+
+}