[GITEA] add option for banning dots in usernames

Refs: https://codeberg.org/forgejo/forgejo/pulls/676

Author:    Panagiotis "Ivory" Vasilopoulos <git@n0toose.net>
Date:      Mon Jun 12 13:57:01 2023 +0200

Co-authored-by: Gusted <postmaster@gusted.xyz>
(cherry picked from commit fabdda5c6e)
(cherry picked from commit d2c7f45621)
(cherry picked from commit dfdbaba3d6)

modules/validation/helpers_test.go

@@ -155,7 +155,8 @@ func Test_IsValidExternalTrackerURLFormat(t *testing.T) {
 	}
 }
 
-func TestIsValidUsername(t *testing.T) {
+func TestIsValidUsernameAllowDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = true
 	tests := []struct {
 		arg  string
 		want bool
@@ -185,3 +186,31 @@ func TestIsValidUsername(t *testing.T) {
 		})
 	}
 }
+
+func TestIsValidUsernameBanDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = false
+	defer func() {
+		setting.Service.AllowDotsInUsernames = true
+	}()
+
+	tests := []struct {
+		arg  string
+		want bool
+	}{
+		{arg: "a", want: true},
+		{arg: "abc", want: true},
+		{arg: "0.b-c", want: false},
+		{arg: "a.b-c_d", want: false},
+		{arg: ".abc", want: false},
+		{arg: "abc.", want: false},
+		{arg: "a..bc", want: false},
+		{arg: "a...bc", want: false},
+		{arg: "a.-bc", want: false},
+		{arg: "a._bc", want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.arg, func(t *testing.T) {
+			assert.Equalf(t, tt.want, IsValidUsername(tt.arg), "IsValidUsername[AllowDotsInUsernames=false](%v)", tt.arg)
+		})
+	}
+}