fix: Retain float microsecond value when formatting datetime

lib/ecto/adapters/sqlite3/codec.ex

@@ -114,16 +114,12 @@ defmodule Ecto.Adapters.SQLite3.Codec do
   end
 
   @text_datetime_format "%Y-%m-%d %H:%M:%S"
-  @iso8601_format "%Y-%m-%dT%H:%M:%S"
-
-  def datetime_format(:text_datetime), do: @text_datetime_format
-  def datetime_format(_), do: @iso8601_format
 
   def utc_datetime_encode(nil, :iso8601), do: {:ok, nil}
   def utc_datetime_encode(nil, :text_datetime), do: {:ok, nil}
 
-  def utc_datetime_encode(%{time_zone: "Etc/UTC"} = value, :iso8601) do
-    {:ok, Calendar.strftime(value, @iso8601_format)}
+  def utc_datetime_encode(%DateTime{time_zone: "Etc/UTC"} = value, :iso8601) do
+    {:ok, DateTime.to_iso8601(value)}
   end
 
   def utc_datetime_encode(%{time_zone: "Etc/UTC"} = value, :text_datetime) do
@@ -139,7 +135,7 @@ defmodule Ecto.Adapters.SQLite3.Codec do
   def naive_datetime_encode(nil, :text_datetime), do: {:ok, nil}
 
   def naive_datetime_encode(value, :iso8601) do
-    {:ok, Calendar.strftime(value, @iso8601_format)}
+    {:ok, NaiveDateTime.to_iso8601(value)}
   end
 
   def naive_datetime_encode(value, :text_datetime) do

lib/ecto/adapters/sqlite3/connection.ex

@@ -1372,7 +1372,14 @@ defmodule Ecto.Adapters.SQLite3.Connection do
   @datetime_type Application.compile_env(:ecto_sqlite3, :datetime_type, :iso8601)
 
   defp expr({:datetime_add, _, [datetime, count, interval]}, sources, query) do
-    format = Ecto.Adapters.SQLite3.Codec.datetime_format(@datetime_type)
+    format =
+      case @datetime_type do
+        :text_datetime ->
+          "%Y-%m-%d %H:%M:%f000Z"
+
+        _ ->
+          "%Y-%m-%dT%H:%M:%f000Z"
+      end
 
     [
       "CAST (",

test/ecto/adapters/sqlite3/codec_test.exs

@@ -144,26 +144,26 @@ defmodule Ecto.Adapters.SQLite3.CodecTest do
   end
 
   describe ".utc_datetime_encode/2" do
-    setup do
-      [dt: ~U[2021-08-25 10:58:59Z]]
-    end
-
     test "nil" do
       assert {:ok, nil} = Codec.utc_datetime_encode(nil, :iso8601)
       assert {:ok, nil} = Codec.utc_datetime_encode(nil, :text_datetime)
     end
 
-    test "iso8601", %{dt: dt} do
-      dt_str = "2021-08-25T10:58:59"
+    test "iso8601" do
+      dt = ~U[2021-08-25 10:58:59Z]
+      dt_str = "2021-08-25T10:58:59Z"
       assert {:ok, ^dt_str} = Codec.utc_datetime_encode(dt, :iso8601)
     end
 
-    test ":text_datetime", %{dt: dt} do
+    test ":text_datetime" do
+      dt = ~U[2021-08-25 10:58:59Z]
       dt_str = "2021-08-25 10:58:59"
       assert {:ok, ^dt_str} = Codec.utc_datetime_encode(dt, :text_datetime)
     end
 
-    test "unknown datetime type", %{dt: dt} do
+    test "unknown datetime type" do
+      dt = ~U[2021-08-25 10:58:59Z]
+
       msg =
         "expected datetime type to be either `:iso8601` or `:text_datetime`, but received `:whatsthis`"
 
@@ -174,26 +174,26 @@ defmodule Ecto.Adapters.SQLite3.CodecTest do
   end
 
   describe ".naive_datetime_encode/2" do
-    setup do
-      [dt: ~U[2021-08-25 10:58:59Z], dt_str: "2021-08-25T10:58:59"]
-    end
-
     test "nil" do
       assert {:ok, nil} = Codec.naive_datetime_encode(nil, :iso8601)
       assert {:ok, nil} = Codec.naive_datetime_encode(nil, :text_datetime)
     end
 
-    test "iso8601", %{dt: dt} do
+    test "iso8601" do
+      dt = ~U[2021-08-25 10:58:59Z]
       dt_str = "2021-08-25T10:58:59"
       assert {:ok, ^dt_str} = Codec.naive_datetime_encode(dt, :iso8601)
     end
 
-    test ":text_datetime", %{dt: dt} do
+    test ":text_datetime" do
+      dt = ~U[2021-08-25 10:58:59Z]
       dt_str = "2021-08-25 10:58:59"
       assert {:ok, ^dt_str} = Codec.naive_datetime_encode(dt, :text_datetime)
     end
 
-    test "unknown datetime type", %{dt: dt} do
+    test "unknown datetime type" do
+      dt = ~U[2021-08-25 10:58:59Z]
+
       msg =
         "expected datetime type to be either `:iso8601` or `:text_datetime`, but received `:whatsthis`"
 

test/ecto/adapters/sqlite3/connection/datetime_add_test.exs

@@ -11,7 +11,7 @@ defmodule Ecto.Adapters.SQLite3.Connection.DatetimeAddTest do
       |> select([], true)
       |> plan()
 
-    assert ~s{SELECT 1 FROM "schema" AS s0 WHERE (CAST (strftime('%Y-%m-%dT%H:%M:%S',s0.\"foo\",1 || ' month') AS TEXT) > s0."bar")} ==
+    assert ~s{SELECT 1 FROM "schema" AS s0 WHERE (CAST (strftime('%Y-%m-%dT%H:%M:%f000Z',s0.\"foo\",1 || ' month') AS TEXT) > s0."bar")} ==
              all(query)
   end
 
@@ -22,7 +22,7 @@ defmodule Ecto.Adapters.SQLite3.Connection.DatetimeAddTest do
       |> select([], true)
       |> plan()
 
-    assert ~s{SELECT 1 FROM "schema" AS s0 WHERE (CAST (strftime('%Y-%m-%dT%H:%M:%S',CAST(s0.\"foo\" AS TEXT),1 || ' month') AS TEXT) > s0."bar")} ==
+    assert ~s{SELECT 1 FROM "schema" AS s0 WHERE (CAST (strftime('%Y-%m-%dT%H:%M:%f000Z',CAST(s0.\"foo\" AS TEXT),1 || ' month') AS TEXT) > s0."bar")} ==
              all(query)
   end
 end

test/ecto/integration/timestamps_test.exs

@@ -197,7 +197,7 @@ defmodule Ecto.Integration.TimestampsTest do
     })
 
     assert [
-             %{name: "Foo"},
+             %{name: "Foo"}
            ] =
              Product
              |> select([p], p)