all: Refactor to nonglobal Viper, i18n etc.

This is a final rewrite that removes all the global state in Hugo, which also enables
the use if `t.Parallel` in tests.

Updates #2701
Fixes #3016

hugolib/testhelpers_test.go

@@ -6,20 +6,64 @@ import (
 
 	"github.com/spf13/hugo/deps"
 	"github.com/spf13/hugo/helpers"
-	"github.com/spf13/hugo/hugofs"
 	"github.com/spf13/hugo/source"
 	"github.com/spf13/hugo/tplapi"
 	"github.com/spf13/viper"
 
+	"io/ioutil"
+	"os"
+
+	"log"
+
+	"github.com/spf13/hugo/hugofs"
+	jww "github.com/spf13/jwalterweatherman"
 	"github.com/stretchr/testify/require"
 )
 
-func newTestDepsConfig() deps.DepsCfg {
-	return deps.DepsCfg{Fs: hugofs.NewMem()}
+func newTestPathSpec(fs *hugofs.Fs, v *viper.Viper) *helpers.PathSpec {
+	l := helpers.NewDefaultLanguage(v)
+	return helpers.NewPathSpec(fs, l)
 }
 
-func newTestPathSpec() *helpers.PathSpec {
-	return helpers.NewPathSpec(hugofs.NewMem(), viper.GetViper())
+func newTestCfg() (*viper.Viper, *hugofs.Fs) {
+
+	v := viper.New()
+	fs := hugofs.NewMem(v)
+
+	v.SetFs(fs.Source)
+
+	loadDefaultSettingsFor(v)
+
+	// Default is false, but true is easier to use as default in tests
+	v.Set("defaultContentLanguageInSubdir", true)
+
+	return v, fs
+
+}
+
+// newTestSite creates a new site in the  English language with in-memory Fs.
+// The site will have a template system loaded and ready to use.
+// Note: This is only used in single site tests.
+func newTestSite(t testing.TB, configKeyValues ...interface{}) *Site {
+
+	cfg, fs := newTestCfg()
+
+	for i := 0; i < len(configKeyValues); i += 2 {
+		cfg.Set(configKeyValues[i].(string), configKeyValues[i+1])
+	}
+
+	d := deps.DepsCfg{Language: helpers.NewLanguage("en", cfg), Fs: fs}
+
+	s, err := NewSiteForCfg(d)
+
+	if err != nil {
+		t.Fatalf("Failed to create Site: %s", err)
+	}
+	return s
+}
+
+func newDebugLogger() *jww.Notepad {
+	return jww.NewNotepad(jww.LevelDebug, jww.LevelError, os.Stdout, ioutil.Discard, "", log.Ldate|log.Ltime)
 }
 
 func createWithTemplateFromNameValues(additionalTemplates ...string) func(templ tplapi.Template) error {
@@ -36,11 +80,21 @@ func createWithTemplateFromNameValues(additionalTemplates ...string) func(templ
 }
 
 func buildSingleSite(t *testing.T, depsCfg deps.DepsCfg, buildCfg BuildCfg) *Site {
-	h, err := NewHugoSitesFromConfiguration(depsCfg)
+	return buildSingleSiteExpected(t, false, depsCfg, buildCfg)
+}
+
+func buildSingleSiteExpected(t *testing.T, expectBuildError bool, depsCfg deps.DepsCfg, buildCfg BuildCfg) *Site {
+	h, err := NewHugoSites(depsCfg)
 
 	require.NoError(t, err)
 	require.Len(t, h.Sites, 1)
 
+	if expectBuildError {
+		require.Error(t, h.Build(buildCfg))
+		return nil
+
+	}
+
 	require.NoError(t, h.Build(buildCfg))
 
 	return h.Sites[0]