GraphQL API token_transfers query

Why:

* For GraphQL API users to be able to fetch token transfer events. RPC
API users could use this instead of the `tokentx` RPC API action.

  Example usage:
  1.
  ```
  query ($token_contract_address_hash: AddressHash!, $first: Int!) {
    token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first) {
      edges {
        node {
          amount
          block_number
          log_index
          token_id
          from_address_hash
          to_address_hash
          token_contract_address_hash
          transaction_hash
        }
      }
    }
  }
  ```

  2. with pagination support via [Relay Cursor
Connections](https://facebook.github.io/relay/graphql/connections.htm)
  ```
  query ($token_contract_address_hash: AddressHash!, $first: Int!, $after: ID!) {
  token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first, after: $after) {
      page_info {
        has_next_page
        has_previous_page
      }
      edges {
        node {
          amount
          from_address_hash
          to_address_hash
        }
        cursor
      }
    }
  }
  ```
* Issue link: n/a

This change addresses the need by:

* Editing the node interface and node field in `BlockScoutWeb.Schema` to
support token transfers.
* Adding `token_transfers` connection field to root query object in
`BlockScoutWeb.Schema`
* Making `token_transfer` object types a node type and adding a few new
fields to it, in `BlockScoutWeb.Schema.Types`.
* Creating `BlockScoutWeb.Resolvers.TokenTransfer` with resolver
functions for getting token transfers.
* Adding `get_token_transfer/1` and `list_token_transfers_query/1` to
`Explorer.GraphQL`. These two functions are used by the new resolver
functions mentioned above.
* Editing RPC API docs to reference the new GraphQL query field added in
this commit.

apps/block_scout_web/lib/block_scout_web/etherscan.ex

@@ -1087,7 +1087,8 @@ defmodule BlockScoutWeb.Etherscan do
 
   @account_tokentx_action %{
     name: "tokentx",
-    description: "Get token transfer events by address. Up to a maximum of 10,000 token transfer events.",
+    description:
+      "Get token transfer events by address. Up to a maximum of 10,000 token transfer events. Also available through a GraphQL 'token_transfers' query.",
     required_params: [
       %{
         key: "address",

apps/block_scout_web/lib/block_scout_web/resolvers/token_transfer.ex

@@ -0,0 +1,24 @@
+defmodule BlockScoutWeb.Resolvers.TokenTransfer do
+  @moduledoc false
+
+  alias Absinthe.Relay.Connection
+  alias Explorer.{GraphQL, Repo}
+
+  def get_by(%{transaction_hash: _, log_index: _} = args) do
+    GraphQL.get_token_transfer(args)
+  end
+
+  def get_by(_, %{token_contract_address_hash: token_contract_address_hash} = args, _) do
+    connection_args = Map.take(args, [:after, :before, :first, :last])
+
+    token_contract_address_hash
+    |> GraphQL.list_token_transfers_query()
+    |> Connection.from_query(&Repo.all/1, connection_args, options(args))
+  end
+
+  defp options(%{before: _}), do: []
+
+  defp options(%{count: count}), do: [count: count]
+
+  defp options(_), do: []
+end

apps/block_scout_web/lib/block_scout_web/schema.ex

@@ -11,23 +11,28 @@ defmodule BlockScoutWeb.Schema do
     Address,
     Block,
     InternalTransaction,
+    TokenTransfer,
     Transaction
   }
 
   alias Explorer.Chain
   alias Explorer.Chain.InternalTransaction, as: ExplorerChainInternalTransaction
+  alias Explorer.Chain.TokenTransfer, as: ExplorerChainTokenTransfer
   alias Explorer.Chain.Transaction, as: ExplorerChainTransaction
 
   import_types(BlockScoutWeb.Schema.Types)
 
   node interface do
     resolve_type(fn
-      %ExplorerChainTransaction{}, _ ->
-        :transaction
-
       %ExplorerChainInternalTransaction{}, _ ->
         :internal_transaction
 
+      %ExplorerChainTokenTransfer{}, _ ->
+        :token_transfer
+
+      %ExplorerChainTransaction{}, _ ->
+        :transaction
+
       _, _ ->
         nil
     end)
@@ -36,15 +41,20 @@ defmodule BlockScoutWeb.Schema do
   query do
     node field do
       resolve(fn
-        %{type: :transaction, id: transaction_hash_string}, _ ->
-          {:ok, hash} = Chain.string_to_transaction_hash(transaction_hash_string)
-          Transaction.get_by(%{}, %{hash: hash}, %{})
-
         %{type: :internal_transaction, id: id}, _ ->
           %{"transaction_hash" => transaction_hash_string, "index" => index} = Jason.decode!(id)
           {:ok, transaction_hash} = Chain.string_to_transaction_hash(transaction_hash_string)
           InternalTransaction.get_by(%{transaction_hash: transaction_hash, index: index})
 
+        %{type: :token_transfer, id: id}, _ ->
+          %{"transaction_hash" => transaction_hash_string, "log_index" => log_index} = Jason.decode!(id)
+          {:ok, transaction_hash} = Chain.string_to_transaction_hash(transaction_hash_string)
+          TokenTransfer.get_by(%{transaction_hash: transaction_hash, log_index: log_index})
+
+        %{type: :transaction, id: transaction_hash_string}, _ ->
+          {:ok, hash} = Chain.string_to_transaction_hash(transaction_hash_string)
+          Transaction.get_by(%{}, %{hash: hash}, %{})
+
         _, _ ->
           {:error, "Unknown node"}
       end)
@@ -69,6 +79,22 @@ defmodule BlockScoutWeb.Schema do
       resolve(&Block.get_by/3)
     end
 
+    @desc "Gets token transfers by token contract address hash."
+    connection field(:token_transfers, node_type: :token_transfer) do
+      arg(:token_contract_address_hash, non_null(:address_hash))
+      arg(:count, :integer)
+
+      resolve(&TokenTransfer.get_by/3)
+
+      complexity(fn
+        %{first: first}, child_complexity ->
+          first * child_complexity
+
+        %{last: last}, child_complexity ->
+          last * child_complexity
+      end)
+    end
+
     @desc "Gets a transaction by hash."
     field :transaction, :transaction do
       arg(:hash, non_null(:full_hash))

apps/block_scout_web/lib/block_scout_web/schema/types.ex

@@ -16,6 +16,7 @@ defmodule BlockScoutWeb.Schema.Types do
 
   connection(node_type: :transaction)
   connection(node_type: :internal_transaction)
+  connection(node_type: :token_transfer)
 
   @desc """
   A stored representation of a Web3 address.
@@ -105,6 +106,20 @@ defmodule BlockScoutWeb.Schema.Types do
     field(:address_hash, :address_hash)
   end
 
+  @desc """
+  Represents a token transfer between addresses.
+  """
+  node object(:token_transfer, id_fetcher: &token_transfer_id_fetcher/2) do
+    field(:amount, :decimal)
+    field(:block_number, :integer)
+    field(:log_index, :integer)
+    field(:token_id, :decimal)
+    field(:from_address_hash, :address_hash)
+    field(:to_address_hash, :address_hash)
+    field(:token_contract_address_hash, :address_hash)
+    field(:transaction_hash, :full_hash)
+  end
+
   @desc """
   Models a Web3 transaction.
   """
@@ -142,15 +157,8 @@ defmodule BlockScoutWeb.Schema.Types do
     end
   end
 
-  @desc """
+  def token_transfer_id_fetcher(%{transaction_hash: transaction_hash, log_index: log_index}, _) do
-  Represents a token transfer between addresses.
+    Jason.encode!(%{transaction_hash: to_string(transaction_hash), log_index: log_index})
-  """
-  object :token_transfer do
-    field(:amount, :decimal)
-    field(:from_address_hash, :address_hash)
-    field(:to_address_hash, :address_hash)
-    field(:token_contract_address_hash, :address_hash)
-    field(:transaction_hash, :full_hash)
   end
 
   def transaction_id_fetcher(%{hash: hash}, _), do: to_string(hash)

apps/block_scout_web/test/block_scout_web/schema/query/node_test.exs

@@ -126,5 +126,72 @@ defmodule BlockScoutWeb.Schema.Query.NodeTest do
 
       assert error["message"] == "Internal transaction not found."
     end
+
+    test "with valid argument 'id' for a token_transfer", %{conn: conn} do
+      transaction = insert(:transaction)
+      token_transfer = insert(:token_transfer, transaction: transaction)
+
+      query = """
+      query($id: ID!) {
+        node(id: $id) {
+          ... on TokenTransfer {
+            id
+            transaction_hash
+            log_index
+          }
+        }
+      }
+      """
+
+      id =
+        %{transaction_hash: to_string(token_transfer.transaction_hash), log_index: token_transfer.log_index}
+        |> Jason.encode!()
+        |> (fn unique_id -> "TokenTransfer:#{unique_id}" end).()
+        |> Base.encode64()
+
+      variables = %{"id" => id}
+
+      conn = get(conn, "/graphql", query: query, variables: variables)
+
+      assert json_response(conn, 200) == %{
+               "data" => %{
+                 "node" => %{
+                   "id" => id,
+                   "transaction_hash" => to_string(token_transfer.transaction_hash),
+                   "log_index" => token_transfer.log_index
+                 }
+               }
+             }
+    end
+
+    test "with id for non-existent token transfer", %{conn: conn} do
+      transaction = build(:transaction)
+
+      query = """
+      query($id: ID!) {
+        node(id: $id) {
+          ... on TokenTransfer {
+            id
+            transaction_hash
+            log_index
+          }
+        }
+      }
+      """
+
+      id =
+        %{transaction_hash: to_string(transaction.hash), log_index: 0}
+        |> Jason.encode!()
+        |> (fn unique_id -> "TokenTransfer:#{unique_id}" end).()
+        |> Base.encode64()
+
+      variables = %{"id" => id}
+
+      conn = get(conn, "/graphql", query: query, variables: variables)
+
+      %{"errors" => [error]} = json_response(conn, 200)
+
+      assert error["message"] == "Token transfer not found."
+    end
   end
 end

apps/block_scout_web/test/block_scout_web/schema/query/token_transfers_test.exs

@@ -0,0 +1,326 @@
+defmodule BlockScoutWeb.Schema.Query.TokenTransfersTest do
+  use BlockScoutWeb.ConnCase
+
+  describe "token_transfers field" do
+    test "with valid argument, returns all expected fields", %{conn: conn} do
+      transaction = insert(:transaction)
+      token_transfer = insert(:token_transfer, transaction: transaction)
+      address_hash = to_string(token_transfer.token_contract_address_hash)
+
+      query = """
+      query ($token_contract_address_hash: AddressHash!, $first: Int!) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first) {
+          edges {
+            node {
+              amount
+              block_number
+              log_index
+              token_id
+              from_address_hash
+              to_address_hash
+              token_contract_address_hash
+              transaction_hash
+            }
+          }
+        }
+      }
+      """
+
+      variables = %{
+        "token_contract_address_hash" => address_hash,
+        "first" => 1
+      }
+
+      conn = get(conn, "/graphql", query: query, variables: variables)
+
+      assert json_response(conn, 200) == %{
+               "data" => %{
+                 "token_transfers" => %{
+                   "edges" => [
+                     %{
+                       "node" => %{
+                         "amount" => to_string(token_transfer.amount),
+                         "block_number" => token_transfer.block_number,
+                         "log_index" => token_transfer.log_index,
+                         "token_id" => token_transfer.token_id,
+                         "from_address_hash" => to_string(token_transfer.from_address_hash),
+                         "to_address_hash" => to_string(token_transfer.to_address_hash),
+                         "token_contract_address_hash" => to_string(token_transfer.token_contract_address_hash),
+                         "transaction_hash" => to_string(token_transfer.transaction_hash)
+                       }
+                     }
+                   ]
+                 }
+               }
+             }
+    end
+
+    test "with token contract address with zero token transfers", %{conn: conn} do
+      address = insert(:contract_address)
+
+      query = """
+      query ($token_contract_address_hash: AddressHash!, $first: Int!) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first) {
+          edges {
+            node {
+              amount
+              block_number
+              log_index
+              token_id
+              from_address_hash
+              to_address_hash
+              token_contract_address_hash
+              transaction_hash
+            }
+          }
+        }
+      }
+      """
+
+      variables = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "first" => 10
+      }
+
+      conn = get(conn, "/graphql", query: query, variables: variables)
+
+      assert json_response(conn, 200) == %{
+               "data" => %{
+                 "token_transfers" => %{
+                   "edges" => []
+                 }
+               }
+             }
+    end
+
+    test "complexity correlates to first or last argument", %{conn: conn} do
+      address = insert(:contract_address)
+
+      query1 = """
+      query ($token_contract_address_hash: AddressHash!, $first: Int!) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first) {
+          edges {
+            node {
+              amount
+              from_address_hash
+              to_address_hash
+            }
+          }
+        }
+      }
+      """
+
+      variables1 = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "first" => 55
+      }
+
+      response1 =
+        conn
+        |> get("/graphql", query: query1, variables: variables1)
+        |> json_response(200)
+
+      %{"errors" => [response1_error1, response1_error2]} = response1
+
+      assert response1_error1["message"] =~ ~s(Field token_transfers is too complex)
+      assert response1_error2["message"] =~ ~s(Operation is too complex)
+
+      query2 = """
+      query ($token_contract_address_hash: AddressHash!, $last: Int!) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, last: $last) {
+          edges {
+            node {
+              amount
+              from_address_hash
+              to_address_hash
+            }
+          }
+        }
+      }
+      """
+
+      variables2 = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "last" => 55
+      }
+
+      response2 =
+        conn
+        |> get("/graphql", query: query2, variables: variables2)
+        |> json_response(200)
+
+      %{"errors" => [response2_error1, response2_error2]} = response2
+      assert response2_error1["message"] =~ ~s(Field token_transfers is too complex)
+      assert response2_error2["message"] =~ ~s(Operation is too complex)
+    end
+
+    test "with 'last' and 'count' arguments", %{conn: conn} do
+      # "`last: N` must always be acompanied by either a `before:` argument to
+      # the query, or an explicit `count:` option to the `from_query` call.
+      # Otherwise it is impossible to derive the required offset."
+      # https://hexdocs.pm/absinthe_relay/Absinthe.Relay.Connection.html#from_query/4
+      #
+      # This test ensures support for a 'count' argument.
+
+      address = insert(:contract_address)
+
+      blocks = insert_list(2, :block)
+
+      [transaction1, transaction2] =
+        for block <- blocks do
+          :transaction
+          |> insert()
+          |> with_block(block)
+        end
+
+      token_transfer_attrs1 = %{
+        block_number: transaction1.block_number,
+        transaction: transaction1,
+        token_contract_address: address
+      }
+
+      token_transfer_attrs2 = %{
+        block_number: transaction2.block_number,
+        transaction: transaction2,
+        token_contract_address: address
+      }
+
+      insert(:token_transfer, token_transfer_attrs1)
+      insert(:token_transfer, token_transfer_attrs2)
+
+      query = """
+      query ($token_contract_address_hash: AddressHash!, $last: Int!, $count: Int) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, last: $last, count: $count) {
+          edges {
+            node {
+              transaction_hash
+            }
+          }
+        }
+      }
+      """
+
+      variables = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "last" => 1,
+        "count" => 2
+      }
+
+      [token_transfer] =
+        conn
+        |> get("/graphql", query: query, variables: variables)
+        |> json_response(200)
+        |> get_in(["data", "token_transfers", "edges"])
+
+      assert token_transfer["node"]["transaction_hash"] == to_string(transaction1.hash)
+    end
+
+    test "pagination support with 'first' and 'after' arguments", %{conn: conn} do
+      address = insert(:contract_address)
+
+      blocks = insert_list(3, :block)
+
+      [transaction1, transaction2, transaction3] =
+        transactions =
+        for block <- blocks do
+          :transaction
+          |> insert()
+          |> with_block(block)
+        end
+
+      for transaction <- transactions do
+        token_transfer_attrs = %{
+          block_number: transaction.block_number,
+          transaction: transaction,
+          token_contract_address: address
+        }
+
+        insert(:token_transfer, token_transfer_attrs)
+      end
+
+      query1 = """
+      query ($token_contract_address_hash: AddressHash!, $first: Int!) {
+        token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first) {
+          page_info {
+            has_next_page
+            has_previous_page
+          }
+          edges {
+            node {
+              transaction_hash
+            }
+            cursor
+          }
+        }
+      }
+      """
+
+      variables1 = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "first" => 1
+      }
+
+      conn = get(conn, "/graphql", query: query1, variables: variables1)
+
+      %{"data" => %{"token_transfers" => page1}} = json_response(conn, 200)
+
+      assert page1["page_info"] == %{"has_next_page" => true, "has_previous_page" => false}
+      assert Enum.all?(page1["edges"], &(&1["node"]["transaction_hash"] == to_string(transaction3.hash)))
+
+      last_cursor_page1 =
+        page1
+        |> Map.get("edges")
+        |> List.last()
+        |> Map.get("cursor")
+
+      query2 = """
+      query ($token_contract_address_hash: AddressHash!, $first: Int!, $after: ID!) {
+      token_transfers(token_contract_address_hash: $token_contract_address_hash, first: $first, after: $after) {
+          page_info {
+            has_next_page
+            has_previous_page
+          }
+          edges {
+            node {
+              transaction_hash
+            }
+            cursor
+          }
+        }
+      }
+      """
+
+      variables2 = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "first" => 1,
+        "after" => last_cursor_page1
+      }
+
+      conn = get(conn, "/graphql", query: query2, variables: variables2)
+
+      %{"data" => %{"token_transfers" => page2}} = json_response(conn, 200)
+
+      assert page2["page_info"] == %{"has_next_page" => true, "has_previous_page" => true}
+      assert Enum.all?(page2["edges"], &(&1["node"]["transaction_hash"] == to_string(transaction2.hash)))
+
+      last_cursor_page2 =
+        page2
+        |> Map.get("edges")
+        |> List.last()
+        |> Map.get("cursor")
+
+      variables3 = %{
+        "token_contract_address_hash" => to_string(address.hash),
+        "first" => 1,
+        "after" => last_cursor_page2
+      }
+
+      conn = get(conn, "/graphql", query: query2, variables: variables3)
+
+      %{"data" => %{"token_transfers" => page3}} = json_response(conn, 200)
+
+      assert page3["page_info"] == %{"has_next_page" => false, "has_previous_page" => true}
+      assert Enum.all?(page3["edges"], &(&1["node"]["transaction_hash"] == to_string(transaction1.hash)))
+    end
+  end
+end

apps/explorer/lib/explorer/graphql.ex

@@ -15,6 +15,7 @@ defmodule Explorer.GraphQL do
     Address,
     Hash,
     InternalTransaction,
+    TokenTransfer,
     Transaction
   }
 
@@ -67,4 +68,32 @@ defmodule Explorer.GraphQL do
 
     Chain.where_transaction_has_multiple_internal_transactions(query)
   end
+
+  @doc """
+  Returns a token transfer for a given transaction hash and log index.
+  """
+  @spec get_token_transfer(map()) :: {:ok, TokenTransfer.t()} | {:error, String.t()}
+  def get_token_transfer(%{transaction_hash: _, log_index: _} = clauses) do
+    if token_transfer = Repo.get_by(TokenTransfer, clauses) do
+      {:ok, token_transfer}
+    else
+      {:error, "Token transfer not found."}
+    end
+  end
+
+  @doc """
+  Returns a query to fetch token transfers for a token contract address hash.
+
+  Orders token transfers by descending block number, descending transaction index, and ascending log index.
+  """
+  @spec list_token_transfers_query(Hash.t()) :: Ecto.Query.t()
+  def list_token_transfers_query(%Hash{byte_count: unquote(Hash.Address.byte_count())} = token_contract_address_hash) do
+    from(
+      tt in TokenTransfer,
+      inner_join: t in assoc(tt, :transaction),
+      where: tt.token_contract_address_hash == ^token_contract_address_hash,
+      order_by: [desc: tt.block_number, desc: t.index, asc: tt.log_index],
+      select: tt
+    )
+  end
 end

apps/explorer/test/explorer/graphql_test.exs

@@ -181,4 +181,129 @@ defmodule Explorer.GraphQLTest do
     #
     # These two requirements are tested in `Explorer.ChainTest`.
   end
+
+  describe "get_token_transfer/1" do
+    test "returns existing token transfer" do
+      transaction = insert(:transaction)
+      token_transfer = insert(:token_transfer, transaction: transaction)
+
+      clauses = %{transaction_hash: token_transfer.transaction_hash, log_index: token_transfer.log_index}
+
+      {:ok, found_token_transfer} = GraphQL.get_token_transfer(clauses)
+
+      assert found_token_transfer.transaction_hash == token_transfer.transaction_hash
+      assert found_token_transfer.log_index == token_transfer.log_index
+    end
+
+    test " returns error tuple for non-existing token transfer" do
+      transaction = insert(:transaction)
+      token_transfer = build(:token_transfer, transaction: transaction)
+
+      clauses = %{transaction_hash: transaction.hash, log_index: token_transfer.log_index}
+
+      assert GraphQL.get_token_transfer(clauses) == {:error, "Token transfer not found."}
+    end
+  end
+
+  describe "list_token_transfers_query/1" do
+    test "with token contract address hash with zero token transfers" do
+      result =
+        :address
+        |> insert()
+        |> Map.get(:hash)
+        |> GraphQL.list_token_transfers_query()
+        |> Repo.all()
+
+      assert result == []
+    end
+
+    test "returns all expected token transfer fields" do
+      transaction = insert(:transaction)
+      token_transfer = insert(:token_transfer, transaction: transaction)
+
+      [found_token_transfer] =
+        token_transfer.token_contract_address_hash
+        |> GraphQL.list_token_transfers_query()
+        |> Repo.all()
+
+      expected_fields = ~w(
+        amount
+        block_number
+        log_index
+        token_id
+        from_address_hash
+        to_address_hash
+        token_contract_address_hash
+        transaction_hash
+      )a
+
+      for expected_field <- expected_fields do
+        assert Map.get(found_token_transfer, expected_field) == Map.get(token_transfer, expected_field)
+      end
+    end
+
+    test "orders token transfers by descending block number, descending transaction index, and ascending log index" do
+      first_block = insert(:block)
+      second_block = insert(:block)
+      third_block = insert(:block)
+
+      transactions_block2 =
+        2
+        |> insert_list(:transaction)
+        |> with_block(second_block)
+
+      transactions_block3 =
+        2
+        |> insert_list(:transaction)
+        |> with_block(third_block)
+
+      transactions_block1 =
+        2
+        |> insert_list(:transaction)
+        |> with_block(first_block)
+
+      all_transactions = Enum.concat([transactions_block2, transactions_block3, transactions_block1])
+
+      token_address = insert(:contract_address)
+      insert(:token, contract_address: token_address)
+
+      for transaction <- all_transactions do
+        token_transfer_attrs1 = %{
+          block_number: transaction.block_number,
+          log_index: 0,
+          transaction: transaction,
+          token_contract_address: token_address
+        }
+
+        token_transfer_attrs2 = %{
+          block_number: transaction.block_number,
+          log_index: 1,
+          transaction: transaction,
+          token_contract_address: token_address
+        }
+
+        insert(:token_transfer, token_transfer_attrs1)
+        insert(:token_transfer, token_transfer_attrs2)
+      end
+
+      found_token_transfers =
+        token_address.hash
+        |> GraphQL.list_token_transfers_query()
+        |> Repo.all()
+        |> Repo.preload(:transaction)
+
+      block_number_order = Enum.map(found_token_transfers, & &1.block_number)
+      transaction_index_order = Enum.map(found_token_transfers, &{&1.block_number, &1.transaction.index})
+
+      assert block_number_order == Enum.sort(block_number_order, &(&1 >= &2))
+      assert transaction_index_order == Enum.sort(transaction_index_order, &(&1 >= &2))
+
+      tt_by_block_transaction = Enum.group_by(found_token_transfers, &{&1.block_number, &1.transaction.index})
+
+      for {_, token_transfers} <- tt_by_block_transaction do
+        log_index_order = Enum.map(token_transfers, & &1.log_index)
+        assert log_index_order == Enum.sort(log_index_order)
+      end
+    end
+  end
 end