luatz/timetable: Optimize and export `is_leap`; add tests

diff --git a/luatz/timetable.lua b/luatz/timetable.lua
index f09637255e7676bc821342dca9e91e0b4ba25e59..99ac52ee8d238f85e350e5e4ed2a92b1fa6b32b6 100644 (file)
--- a/luatz/timetable.lua
+++ b/luatz/timetable.lua
@@ -16,7 +16,13 @@ end
 local sakamoto = {0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4};
 
 local function is_leap ( y )
-       return (y % 4) == 0 and (y % 100) ~= 0 or (y % 400) == 0
+       if (y % 4) ~= 0 then
+               return false
+       elseif (y % 100) ~= 0 then
+               return true
+       else
+               return (y % 400) == 0
+       end
 end
 
 local function year_length ( y )
@@ -200,6 +206,7 @@ local function new_from_timestamp ( ts )
 end
 
 return {
+       is_leap = is_leap ;
        day_of_year = day_of_year ;
        day_of_week = day_of_week ;
        normalise = normalise ;

diff --git a/spec/timetable_spec.lua b/spec/timetable_spec.lua
index b76991159cd775c083698c8e81a72c8e1323a753..0ff42b12d7bbccb894a2f0143481dcb10278afc9 100644 (file)
--- a/spec/timetable_spec.lua
+++ b/spec/timetable_spec.lua
@@ -9,6 +9,19 @@ describe ( "Timetable library" , function ( )
                })
        end
 
+       it ( "#is_leap is correct" , function ( )
+               assert.same ( false , timetable.is_leap ( 1 ) )
+               assert.same ( false , timetable.is_leap ( 3 ) )
+               assert.same ( true  , timetable.is_leap ( 4 ) )
+               assert.same ( true  , timetable.is_leap ( 2000 ) )
+               assert.same ( true  , timetable.is_leap ( 2004 ) )
+               assert.same ( true  , timetable.is_leap ( 2012 ) )
+               assert.same ( false , timetable.is_leap ( 2013 ) )
+               assert.same ( false , timetable.is_leap ( 2014 ) )
+               assert.same ( false , timetable.is_leap ( 2100 ) )
+               assert.same ( true  , timetable.is_leap ( 2400 ) )
+       end )
+
        it ( "#normalise gets #wday (day of week) correct" , function ( )
 
                local function assert_same_wday ( year , month , day )