Time#days_in_year returns the no of days in a given year (#5163)

crystal-lang · Oct 25, 2017 · c8ee444 · c8ee444
1 parent 08aaa7b
commit c8ee444
Showing 2 changed files with 41 additions and 0 deletions.
diff --git a/spec/std/time/time_spec.cr b/spec/std/time/time_spec.cr
@@ -646,6 +646,32 @@ describe Time do
     (local - utc).should eq(0.seconds)
   end
 
+  describe "days in month" do
+    it "returns days for valid month and year" do
+      Time.days_in_month(2016, 2).should eq(29)
+      Time.days_in_month(1990, 4).should eq(30)
+    end
+
+    it "raises exception for invalid month" do
+      expect_raises(ArgumentError, "Invalid month") do
+        Time.days_in_month(2016, 13)
+      end
+    end
+
+    it "raises exception for invalid year" do
+      expect_raises(ArgumentError, "Invalid year") do
+        Time.days_in_month(10000, 11)
+      end
+    end
+  end
+
+  it "days in year with year" do
+    Time.days_in_year(2005).should eq(365)
+    Time.days_in_year(2004).should eq(366)
+    Time.days_in_year(2000).should eq(366)
+    Time.days_in_year(1990).should eq(365)
+  end
+
   typeof(Time.now.year)
   typeof(1.minute.from_now.year)
   typeof(1.minute.ago.year)

diff --git a/src/time.cr b/src/time.cr
@@ -405,6 +405,11 @@ struct Time
   def_hash total_seconds, nanosecond
 
   # Returns how many days this *month* (`1..12`) of this *year* has (28, 29, 30 or 31).
+  #
+  # ```
+  # Time.days_in_month(2016, 2) # => 29
+  # Time.days_in_month(1990, 4) # => 30
+  # ```
   def self.days_in_month(year : Int, month : Int) : Int32
     unless 1 <= month <= 12
       raise ArgumentError.new "Invalid month"
@@ -418,6 +423,16 @@ struct Time
     days[month]
   end
 
+  # Returns number of days in *year*.
+  #
+  # ```
+  # Time.days_in_year(1990) # => 365
+  # Time.days_in_year(2004) # => 366
+  # ```
+  def self.days_in_year(year : Int) : Int32
+    leap_year?(year) ? 366 : 365
+  end
+
   # Returns whether this *year* is leap (February has one more day).
   def self.leap_year?(year : Int) : Bool
     unless 1 <= year <= 9999