removed Formatduration and fixed rounding error, working on overtime calculation

Backend/helper/time_test.go

@@ -15,3 +15,22 @@ func TestGetMonday(t *testing.T) {
 		t.Error("Wrong date conversion!")
 	}
 }
+
+func TestFormatDuration(t *testing.T) {
+	durations := []struct {
+		name     string
+		duration time.Duration
+	}{
+		{"2h", time.Duration(120 * time.Minute)},
+		{"30min", time.Duration(30 * time.Minute)},
+		{"1h 30min", time.Duration(90 * time.Minute)},
+		{"-1h 30min", time.Duration(-90 * time.Minute)},
+	}
+	for _, d := range durations {
+		t.Run(d.name, func(t *testing.T) {
+			if FormatDuration(d.duration) != d.name {
+				t.Error("Format missmatch in Formatduration.")
+			}
+		})
+	}
+}