[OP-19966] Fix 500 when creating working hours with a nil weekday

app/models/user_working_hours.rb

@@ -72,7 +72,8 @@ def self.current
 
   DAYS.each do |day|
     define_method("#{day}_hours") do
-      (public_send(day) / 60.0).round(2)
+      minutes = public_send(day)
+      minutes.nil? ? nil : (minutes / 60.0).round(2)
     end
 
     define_method("#{day}_hours=") do |value|
@@ -158,7 +159,7 @@ def abbr_day_name(day)
   end
 
   def at_least_one_working_day_selected
-    if DAYS.all? { |day| public_send(day).zero? }
+    if DAYS.all? { |day| public_send(day).to_i.zero? }
       errors.add(:days, :no_working_day)
     end
   end

spec/models/user_working_hours_spec.rb

@@ -74,6 +74,34 @@
                                                                        .is_greater_than_or_equal_to(0)
                                                                        .is_less_than_or_equal_to(100)
     end
+
+    describe "with a nil weekday column (e.g. omitted from a create payload)" do
+      # Regression tests: presence/numericality validation on a `*_hours`
+      # attribute invokes the corresponding getter, which used to crash with
+      # NoMethodError on `nil / 60.0` instead of producing a clean
+      # validation error.
+      it "is invalid rather than raising when a single weekday is nil" do
+        subject.public_send(:wednesday=, nil)
+
+        expect { subject.valid? }.not_to raise_error
+        expect(subject).not_to be_valid
+        expect(subject.errors[:wednesday_hours]).to be_present
+      end
+
+      it "is invalid rather than raising when every weekday is nil" do
+        # Also exercises the second, independent nil-unsafe site in
+        # at_least_one_working_day_selected, only reachable once every
+        # weekday is nil (each weekday's own presence/numericality
+        # validation would otherwise short-circuit first).
+        %i[monday tuesday wednesday thursday friday saturday sunday].each do |day|
+          subject.public_send(:"#{day}=", nil)
+        end
+
+        expect { subject.valid? }.not_to raise_error
+        expect(subject).not_to be_valid
+        expect(subject.errors[:days]).to be_present
+      end
+    end
   end
 
   describe "hours accessors" do
@@ -85,6 +113,15 @@
           working_hours.public_send("#{day}=", 150)
           expect(working_hours.public_send("#{day}_hours")).to eq(2.5)
         end
+
+        it "returns nil rather than raising when the underlying minutes column is nil" do
+          # Regression test: a still-nil column (e.g. a weekday omitted from
+          # a create payload, no DB default) used to crash with
+          # NoMethodError on `nil / 60.0` -- both here, and via the
+          # presence/numericality validator that calls this same getter.
+          working_hours.public_send("#{day}=", nil)
+          expect(working_hours.public_send("#{day}_hours")).to be_nil
+        end
       end
 
       describe "##{day}_hours=" do