upped test coverage of helpers

Backend/helper/time_test.go

@@ -26,7 +26,7 @@ func TestGetMonday(t *testing.T) {
 	}
 }
 
-func TestFormatDuration(t *testing.T) {
+func TestFormatDurationFill(t *testing.T) {
 	testCases := []struct {
 		name     string
 		duration time.Duration
@@ -48,6 +48,22 @@ func TestFormatDuration(t *testing.T) {
 	}
 }
 
+func TestFormatDuration(t *testing.T) {
+	testCases := []struct {
+		name     string
+		duration time.Duration
+	}{
+		{"", 0},
+	}
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			if FormatDuration(tc.duration) != tc.name {
+				t.Error("Format missmatch in Formatduration.")
+			}
+		})
+	}
+}
+
 func TestIsSameDate(t *testing.T) {
 	testCases := []struct {
 		dateA  string
@@ -116,3 +132,41 @@ func TestFormatGermanDayOfWeek(t *testing.T) {
 		})
 	}
 }
+
+func TestGetKW(t *testing.T) {
+	tests := []struct {
+		name string
+		date time.Time
+		want int
+	}{
+		{
+			name: "First week of year",
+			date: time.Date(2023, 1, 2, 0, 0, 0, 0, time.UTC), // Monday
+			want: 1,
+		},
+		{
+			name: "Middle of year",
+			date: time.Date(2023, 6, 15, 0, 0, 0, 0, time.UTC),
+			want: 24,
+		},
+		{
+			name: "Last week of year",
+			date: time.Date(2023, 12, 31, 0, 0, 0, 0, time.UTC),
+			want: 52,
+		},
+		{
+			name: "ISO week crossing into next year",
+			date: time.Date(2020, 12, 31, 0, 0, 0, 0, time.UTC),
+			want: 53,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := GetKW(tt.date)
+			if got != tt.want {
+				t.Errorf("GetKW(%v) = %d, want %d", tt.date, got, tt.want)
+			}
+		})
+	}
+}