2 files changed, 44 insertions, 60 deletions
diff --git a/internal/validate/formvalidation.go b/internal/validate/formvalidation.go
index 76ce6a8de..1b5996b4b 100644
--- a/internal/validate/formvalidation.go
+++ b/internal/validate/formvalidation.go
@@ -99,14 +99,19 @@ func Email(email string) error {
 	return err
 }
 
-// Language checks that the given language string is a 2- or 3-letter ISO 639 code.
-// Returns an error if the language cannot be parsed. See: https://pkg.go.dev/golang.org/x/text/language
-func Language(lang string) error {
+// Language checks that the given language string is a valid, if not necessarily canonical, BCP 47 language tag.
+// Returns a canonicalized version of the tag if the language can be parsed.
+// Returns an error if the language cannot be parsed.
+// See: https://pkg.go.dev/golang.org/x/text/language
+func Language(lang string) (string, error) {
 	if lang == "" {
-		return errors.New("no language provided")
+		return "", errors.New("no language provided")
 	}
-	_, err := language.ParseBase(lang)
-	return err
+	parsed, err := language.Parse(lang)
+	if err != nil {
+		return "", err
+	}
+	return parsed.String(), err
 }
 
 // SignUpReason checks that a sufficient reason is given for a server signup request
diff --git a/internal/validate/formvalidation_test.go b/internal/validate/formvalidation_test.go
index 534e5b849..40830407c 100644
--- a/internal/validate/formvalidation_test.go
+++ b/internal/validate/formvalidation_test.go
@@ -159,60 +159,39 @@ func (suite *ValidationTestSuite) TestValidateEmail() {
 }
 
 func (suite *ValidationTestSuite) TestValidateLanguage() {
-	empty := ""
-	notALanguage := "this isn't a language at all!"
-	english := "en"
-	capitalEnglish := "EN"
-	arabic3Letters := "ara"
-	mixedCapsEnglish := "eN"
-	englishUS := "en-us"
-	dutch := "nl"
-	german := "de"
-	var err error
-
-	err = validate.Language(empty)
-	if suite.Error(err) {
-		suite.Equal(errors.New("no language provided"), err)
-	}
-
-	err = validate.Language(notALanguage)
-	if suite.Error(err) {
-		suite.Equal(errors.New("language: tag is not well-formed"), err)
-	}
-
-	err = validate.Language(english)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
-	}
-
-	err = validate.Language(capitalEnglish)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
-	}
-
-	err = validate.Language(arabic3Letters)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
-	}
-
-	err = validate.Language(mixedCapsEnglish)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
-	}
-
-	err = validate.Language(englishUS)
-	if suite.Error(err) {
-		suite.Equal(errors.New("language: tag is not well-formed"), err)
-	}
-
-	err = validate.Language(dutch)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
-	}
-
-	err = validate.Language(german)
-	if suite.NoError(err) {
-		suite.Equal(nil, err)
+	testCases := []struct {
+		name, input, expected, err string
+	}{
+		{name: "empty", err: "no language provided"},
+		{name: "notALanguage", input: "this isn't a language at all!", err: "language: tag is not well-formed"},
+		{name: "english", input: "en", expected: "en"},
+		// Should be all lowercase
+		{name: "capitalEnglish", input: "EN", expected: "en"},
+		// Overlong, should be in ISO 639-1 format
+		{name: "arabic3Letters", input: "ara", expected: "ar"},
+		// Should be all lowercase
+		{name: "mixedCapsEnglish", input: "eN", expected: "en"},
+		// Region should be capitalized
+		{name: "englishUS", input: "en-us", expected: "en-US"},
+		{name: "dutch", input: "nl", expected: "nl"},
+		{name: "german", input: "de", expected: "de"},
+		{name: "chinese", input: "zh", expected: "zh"},
+		{name: "chineseSimplified", input: "zh-Hans", expected: "zh-Hans"},
+		{name: "chineseTraditional", input: "zh-Hant", expected: "zh-Hant"},
+	}
+
+	for _, testCase := range testCases {
+		testCase := testCase
+		suite.Run(testCase.name, func() {
+			actual, actualErr := validate.Language(testCase.input)
+			if testCase.err == "" {
+				suite.Equal(testCase.expected, actual)
+				suite.NoError(actualErr)
+			} else {
+				suite.Empty(actual)
+				suite.EqualError(actualErr, testCase.err)
+			}
+		})
 	}
 }