Add rudimentary support for calculating distance traveled at a given …

…pace/duration

lib/runby_pace/run_math.rb

@@ -10,5 +10,17 @@ def self.convert_speed_to_pace(units_per_hour)
       raise 'units_per_hour must be numeric' unless units_per_hour.is_a? Numeric
       RunbyPace::PaceTime.from_minutes(60.0 / units_per_hour)
     end
+
+    def self.distance_traveled(pace, time)
+      # TODO: I sense the need for a refactor...
+      #  Consider extracting a new Pace class, which consists of Time + Units
+      #  Then move this method to the new class, and give it a better name.
+      pace = RunbyPace::PaceTime.new(pace)
+      time = RunbyPace::PaceTime.new(time)
+
+      divisor = pace.total_minutes / time.total_minutes
+      distance_units_traveled = 1 / divisor
+      return distance_units_traveled
+    end
   end
 end

spec/runby_pace/run_math_spec.rb

@@ -14,4 +14,13 @@
       expect(pace).to eq '08:34'
     end
   end
+
+  describe 'distance calculations' do
+    it 'calculates distance traveled, given a pace and a duration in seconds' do
+      pace = '06:00'
+      duration = '60:00'
+      meters_traveled = RunbyPace::RunMath.distance_traveled(pace, duration)
+      expect(meters_traveled).to be_within(0.01).of(10)
+    end
+  end
 end