fix: datetime conversion units (#61)

Signed-off-by: Gabriele Ghio <gabriele.ghio@secomind.com>

Author: shinnokdisengir

lib/astarte/common/generators/datetime.ex

@@ -30,11 +30,11 @@ defmodule Astarte.Common.Generators.DateTime do
 
   @doc false
   @spec min_default :: DateTime.t()
-  def min_default, do: TimestampGenerator.min_default() |> DateTime.from_unix!(@ref_unit)
+  def min_default, do: TimestampGenerator.min_default(@ref_unit) |> DateTime.from_unix!(@ref_unit)
 
   @doc false
   @spec max_default :: DateTime.t()
-  def max_default, do: TimestampGenerator.max_default() |> DateTime.from_unix!(@ref_unit)
+  def max_default, do: TimestampGenerator.max_default(@ref_unit) |> DateTime.from_unix!(@ref_unit)
 
   @doc """
   Generates a random DateTime from min to max (see Timestamp generator)

test/astarte/common/generators/datetime_test.exs

@@ -24,6 +24,7 @@ defmodule Astarte.Common.Generators.DateTimeTest do
   use ExUnitProperties
 
   alias Astarte.Common.Generators.DateTime, as: DateTimeGenerator
+  alias Astarte.Common.Generators.Timestamp, as: TimestampGenerator
 
   @moduletag :common
   @moduletag :datetime
@@ -53,5 +54,17 @@ defmodule Astarte.Common.Generators.DateTimeTest do
         assert DateTime.after?(to, from)
       end
     end
+
+    @tag :issue
+    test "min equals to Timestamp min" do
+      min = TimestampGenerator.min_default(:microsecond) |> DateTime.from_unix!(:microsecond)
+      assert min == DateTimeGenerator.min_default()
+    end
+
+    @tag :issue
+    test "max equals to Timestamp max" do
+      max = TimestampGenerator.max_default(:microsecond) |> DateTime.from_unix!(:microsecond)
+      assert max == DateTimeGenerator.max_default()
+    end
   end
 end