Refine tests and foreign key constraints around transactions.block_id

lib/explorer/transaction.ex

@@ -15,11 +15,14 @@ defmodule Explorer.Transaction do
     belongs_to :block, Explorer.Block
   end
 
+  @required_attrs ~w(hash)a
+  @optional_attrs ~w()a
+
   @doc false
-  def changeset(%Transaction{} = block, attrs) do
-    block
-    |> cast(attrs, [:block_id, :hash])
-    |> validate_required([:block_id, :hash])
+  def changeset(%Transaction{} = transaction, attrs \\ :empty) do
+    transaction
+    |> cast(attrs, [:block_id | @required_attrs], @optional_attrs)
+    |> validate_required(@required_attrs)
     |> foreign_key_constraint(:block_id)
     |> update_change(:hash, &String.downcase/1)
     |> unique_constraint(:hash)

test/explorer/transaction_test.exs

@@ -6,19 +6,19 @@ defmodule Explorer.TransactionTest do
   describe "changeset/2" do
     test "with valid attributes" do
       block = insert(:block)
-      changeset = Transaction.changeset(%Transaction{}, %{block_id: block.id, hash: "0x0"})
-      assert(changeset.valid?)
+      changeset = Transaction.changeset(%Transaction{}, %{hash: "0x0", block_id: block.id})
+      assert changeset.valid?
     end
 
-    test "with an invalid block" do
-      {:error, changeset} = Transaction.changeset(%Transaction{}, %{block_id: 0, hash: "0x0"}) |> Repo.insert
-      assert changeset.errors == [block_id: {"does not exist", []}]
+    test "with a block that does not exist in the database" do
+      {:error, changeset} = Transaction.changeset(%Transaction{}, %{hash: "0x0", block_id: 0}) |> Repo.insert
       refute changeset.valid?
+      assert [block_id: {"does not exist", []}] = changeset.errors
     end
 
     test "with invalid attributes" do
       changeset = Transaction.changeset(%Transaction{}, %{racecar: "yellow ham"})
-      refute(changeset.valid?)
+      refute changeset.valid?
     end
   end
 end