Optimize the multilanguage build process

Work In Progress!

This commit makes a rework of the build and rebuild process to better suit a multi-site setup.

This also includes a complete overhaul of the site tests. Previous these were a messy mix that
were testing just small parts of the build chain, some of it testing code-paths not even used in
"real life". Now all tests that depends on a built site follows the same and real production code path.

See #2309
Closes #2211
Closes #477
Closes #1744

source/file.go

@@ -108,10 +108,11 @@ func (f *File) Path() string {
 }
 
 // NewFileWithContents creates a new File pointer with the given relative path and
-// content.
+// content. The language defaults to "en".
 func NewFileWithContents(relpath string, content io.Reader) *File {
 	file := NewFile(relpath)
 	file.Contents = content
+	file.lang = "en"
 	return file
 }
 
@@ -124,15 +125,16 @@ func NewFile(relpath string) *File {
 	f.dir, f.logicalName = filepath.Split(f.relpath)
 	f.ext = strings.TrimPrefix(filepath.Ext(f.LogicalName()), ".")
 	f.baseName = helpers.Filename(f.LogicalName())
-	if viper.GetBool("Multilingual") {
-		f.lang = strings.TrimPrefix(filepath.Ext(f.baseName), ".")
+
+	f.lang = strings.TrimPrefix(filepath.Ext(f.baseName), ".")
+	if f.lang == "" {
+		f.lang = viper.GetString("DefaultContentLanguage")
 		if f.lang == "" {
-			f.lang = viper.GetString("DefaultContentLanguage")
+			// TODO(bep) ml
+			f.lang = "en"
 		}
-		f.translationBaseName = helpers.Filename(f.baseName)
-	} else {
-		f.translationBaseName = f.baseName
 	}
+	f.translationBaseName = helpers.Filename(f.baseName)
 
 	f.section = helpers.GuessSection(f.Dir())
 	f.uniqueID = helpers.Md5String(f.LogicalName())

source/filesystem.go

@@ -105,6 +105,9 @@ func (f *Filesystem) captureFiles() {
 
 	if err != nil {
 		jww.ERROR.Println(err)
+		if err == helpers.WalkRootTooShortError {
+			panic("The root path is too short. If this is a test, make sure to init the content paths.")
+		}
 	}
 
 }

source/filesystem_test.go

@@ -22,7 +22,7 @@ import (
 )
 
 func TestEmptySourceFilesystem(t *testing.T) {
-	src := new(Filesystem)
+	src := &Filesystem{Base: "Empty"}
 	if len(src.Files()) != 0 {
 		t.Errorf("new filesystem should contain 0 files.")
 	}