1 files changed, 63 insertions, 0 deletions
diff --git a/internal/i18n/i18n_test.go b/internal/i18n/i18n_test.go
new file mode 100644
index 0000000..e735b58
--- /dev/null
+++ b/internal/i18n/i18n_test.go
@@ -0,0 +1,63 @@
+package i18n
+
+import (
+	"testing"
+	"time"
+)
+
+func TestFormatDate(t *testing.T) {
+	at := time.Date(2026, 9, 3, 10, 0, 0, 0, time.UTC)
+	for _, c := range []struct{ lang, style, want string }{
+		{"en", "long", "3 September 2026"}, {"en", "short", "3 Sep 2026"}, {"en", "iso", "2026-09-03"},
+		{"el", "long", "3 Σεπτεμβρίου 2026"}, {"el", "short", "3 Σεπ 2026"}, {"el", "iso", "2026-09-03"},
+		{"xx", "long", "3 September 2026"}, // unknown language reads as English
+	} {
+		if got := FormatDate(c.lang, c.style, at); got != c.want {
+			t.Errorf("%s/%s: got %q, want %q", c.lang, c.style, got, c.want)
+		}
+	}
+}
+
+func TestMonth(t *testing.T) {
+	if got := Month("en", time.May); got != "May" {
+		t.Errorf("en: %q", got)
+	}
+	if got := Month("el", time.May); got != "Μάιος" {
+		t.Errorf("el: %q", got)
+	}
+	for _, tbl := range monthTables {
+		for i := 0; i < 12; i++ {
+			if tbl.name[i] == "" || tbl.inDate[i] == "" || tbl.short[i] == "" {
+				t.Errorf("month %d has an empty name", i+1)
+			}
+		}
+	}
+}
+
+func TestTranslate(t *testing.T) {
+	if T("el", "Save") != "Αποθήκευση" || T("en", "Save") != "Save" || T("el", "no such key") != "no such key" {
+		t.Error("T")
+	}
+	if got := Tf("el", "Page %d of %d", 2, 5); got != "Σελίδα 2 από 5" {
+		t.Errorf("Tf: %q", got)
+	}
+	for _, l := range Languages() {
+		if !Valid(l.Code) {
+			t.Errorf("%s not valid", l.Code)
+		}
+	}
+	if Valid("") || Valid("fr") {
+		t.Error("Valid accepts unknown codes")
+	}
+}
+
+func TestMatch(t *testing.T) {
+	for header, want := range map[string]string{
+		"": "en", "fr": "en", "el": "el", "el-GR,el;q=0.9,en;q=0.8": "el", "en-US,en;q=0.9,el;q=0.8": "en",
+		"fr-FR, EL;q=0.5": "el", "*": "en",
+	} {
+		if got := Match(header); got != want {
+			t.Errorf("%q: got %q, want %q", header, got, want)
+		}
+	}
+}