Return transit data instead of nil for never rising bodies

lib/astronoby/events/observation_events.rb

@@ -52,6 +52,9 @@ def initialize(
       private
 
       def compute
+        @transit_time = Util::Time.decimal_hour_to_time(@date, initial_transit)
+        @transit_altitude = local_horizontal_altitude_transit
+
         return if h0.nil?
 
         delta_m_rising = (local_horizontal_altitude_rising - shift).degrees./(
@@ -72,7 +75,6 @@ def compute
         @rising_time = Util::Time.decimal_hour_to_time(@date, corrected_rising)
         @rising_azimuth = local_horizontal_azimuth_rising
         @transit_time = Util::Time.decimal_hour_to_time(@date, corrected_transit)
-        @transit_altitude = local_horizontal_altitude_transit
         @setting_time = Util::Time.decimal_hour_to_time(@date, corrected_setting)
         @setting_azimuth = local_horizontal_azimuth_setting
       end
@@ -174,7 +176,6 @@ def local_horizontal_altitude_rising
       end
 
       def local_horizontal_azimuth_rising
-        # TODO: What happens if the body doesn't rise or is circumpolar?
         @local_horizontal_azimuth_rising ||= begin
           shift = -@standard_altitude
           term1 = declination_rising.sin + shift.sin * @observer.latitude.cos
@@ -185,7 +186,6 @@ def local_horizontal_azimuth_rising
       end
 
       def local_horizontal_altitude_transit
-        # TODO: What happens if the body doesn't rise/set or is circumpolar?
         @local_horizontal_altitude_transit ||= Angle.asin(
           @observer.latitude.sin * declination_transit.sin +
             @observer.latitude.cos * declination_transit.cos * local_hour_angle_transit.cos
@@ -200,7 +200,6 @@ def local_horizontal_altitude_setting
       end
 
       def local_horizontal_azimuth_setting
-        # TODO: What happens if the body doesn't set or is circumpolar?
         shift = -@standard_altitude
         term1 = declination_setting.sin + shift.sin * @observer.latitude.cos
         term2 = shift.cos * @observer.latitude.cos

spec/astronoby/events/observation_events_spec.rb

@@ -280,7 +280,7 @@
     end
 
     context "when the body does not rise" do
-      it "returns nil" do
+      it "returns an object's upper transit time" do
         date = Date.new(2016, 1, 21)
         observer = Astronoby::Observer.new(
           latitude: Astronoby::Angle.from_degrees(38),
@@ -300,7 +300,33 @@
 
         transit_time = events.transit_time
 
-        expect(transit_time).to be_nil
+        expect(transit_time).to eq Time.utc(2016, 1, 21, 0, 8, 2)
+      end
+    end
+
+    context "when the body is circumpolar" do
+      it "returns an object's upper transit time" do
+        date = Date.new(2016, 1, 21)
+        observer = Astronoby::Observer.new(
+          latitude: Astronoby::Angle.from_degrees(38),
+          longitude: Astronoby::Angle.from_degrees(-78)
+        )
+        coordinates_of_the_day = Astronoby::Coordinates::Equatorial.new(
+          right_ascension: Astronoby::Angle.from_hms(2, 52, 43),
+          declination: Astronoby::Angle.from_dms(89, 20, 9)
+        )
+        events = described_class.new(
+          observer: observer,
+          date: date,
+          coordinates_of_the_previous_day: coordinates_of_the_day,
+          coordinates_of_the_day: coordinates_of_the_day,
+          coordinates_of_the_next_day: coordinates_of_the_day
+        )
+
+        transit_time = events.transit_time
+
+        expect(transit_time).to eq Time.utc(2016, 1, 21, 0, 0, 14)
+        # Time from Stellarium: 2016-01-21T00:01:35
       end
     end
   end
@@ -537,5 +563,31 @@
       expect(transit_altitude.str(:dms)).to eq "+89° 4′ 6.548″"
       # Azimuth from SkySafari: +89° 12′ 1.4″
     end
+
+    context "when the body is circumpolar" do
+      it "returns an object's upper transit azimuth" do
+        date = Date.new(2016, 1, 21)
+        observer = Astronoby::Observer.new(
+          latitude: Astronoby::Angle.from_degrees(38),
+          longitude: Astronoby::Angle.from_degrees(-78)
+        )
+        coordinates_of_the_day = Astronoby::Coordinates::Equatorial.new(
+          right_ascension: Astronoby::Angle.from_hms(2, 52, 43),
+          declination: Astronoby::Angle.from_dms(89, 20, 9)
+        )
+        events = described_class.new(
+          observer: observer,
+          date: date,
+          coordinates_of_the_previous_day: coordinates_of_the_day,
+          coordinates_of_the_day: coordinates_of_the_day,
+          coordinates_of_the_next_day: coordinates_of_the_day
+        )
+
+        transit_altitude = events.transit_altitude
+
+        expect(transit_altitude.str(:dms)).to eq "+38° 39′ 50.9999″"
+        # Azimuth from Stellarium: +38° 41′ 5.4″
+      end
+    end
   end
 end