Pull out the last five Blocks when loading the homepage.

lib/explorer_web/controllers/page_controller.ex

@@ -1,7 +1,15 @@
 defmodule ExplorerWeb.PageController do
   use ExplorerWeb, :controller
+  import Ecto.Query
+  alias Explorer.Block
+  alias Explorer.Repo
 
   def index(conn, _params) do
-    render conn, "index.html"
+    blocks = Block
+      |> order_by(desc: :inserted_at)
+      |> limit(5)
+      |> Repo.all
+
+    render(conn, "index.html", blocks: blocks)
   end
 end

test/explorer/block_test.exs

@@ -5,22 +5,22 @@ defmodule Explorer.BlockTest do
 
   describe "changeset/2" do
     test "with invalid attributes" do
-      changeset = Block.changeset(%Block{}, %{racecar: "yellow ham"})
+      changeset = %Block{} |> Block.changeset(%{racecar: "yellow ham"})
       refute(changeset.valid?)
     end
 
     test "with duplicate information" do
       insert(:block, hash: "0x0")
-      {:error, changeset} = Block.changeset(%Block{}, params_for(:block, hash: "0x0")) |> Repo.insert
-      assert changeset.errors == [hash: {"has already been taken", []}]
+      {:error, changeset} = %Block{} |> Block.changeset(params_for(:block, hash: "0x0")) |> Repo.insert
       refute changeset.valid?
+      assert changeset.errors == [hash: {"has already been taken", []}]
     end
 
     test "rejects duplicate blocks with mixed case" do
       insert(:block, hash: "0xa")
-      {:error, changeset} = Block.changeset(%Block{}, params_for(:block, hash: "0xA")) |> Repo.insert
-      assert changeset.errors == [hash: {"has already been taken", []}]
+      {:error, changeset} = %Block{} |> Block.changeset(params_for(:block, hash: "0xA")) |> Repo.insert
       refute changeset.valid?
+      assert changeset.errors == [hash: {"has already been taken", []}]
     end
   end
 end

test/explorer_web/controllers/page_controller_test.exs

@@ -1,8 +1,23 @@
 defmodule ExplorerWeb.PageControllerTest do
   use ExplorerWeb.ConnCase
 
-  test "GET /", %{conn: conn} do
-    conn = get conn, "/"
-    assert html_response(conn, 200) =~ "Welcome"
+  describe "GET index/2" do
+    test "returns a welcome message", %{conn: conn} do
+      conn = get conn, "/"
+      assert html_response(conn, 200) =~ "Welcome"
+    end
+
+    test "returns a block", %{conn: conn} do
+      block = insert(:block, %{number: 23})
+      conn = get conn, "/"
+      assert(List.first(conn.assigns.blocks) == block)
+    end
+
+    test "excludes all but the most recent five blocks", %{conn: conn} do
+      old_block = insert(:block)
+      insert_list(5, :block)
+      conn = get conn, "/"
+      refute(Enum.member?(conn.assigns.blocks, old_block))
+    end
   end
 end

test/support/conn_case.ex

@@ -23,6 +23,8 @@ defmodule ExplorerWeb.ConnCase do
 
       # The default endpoint for testing
       @endpoint ExplorerWeb.Endpoint
+
+      import Explorer.Factory
     end
   end
 

test/support/factories/block_factory.ex

@@ -3,16 +3,16 @@ defmodule Explorer.BlockFactory do
     quote do
       def block_factory do
         %Explorer.Block{
-          number: 1,
-          hash: "0x0",
-          parent_hash: "0x0",
-          nonce: "1",
-          miner: "0x0",
-          difficulty: 1,
-          total_difficulty: 1,
-          size: 0,
-          gas_limit: 0,
-          gas_used: 0,
+          number: sequence(""),
+          hash: sequence("0x"),
+          parent_hash: sequence("0x"),
+          nonce: sequence(""),
+          miner: sequence("0x"),
+          difficulty: Enum.random(1..100_000),
+          total_difficulty: Enum.random(1..100_000),
+          size: Enum.random(1..100_000),
+          gas_limit: Enum.random(1..100_000),
+          gas_used: Enum.random(1..100_000),
           timestamp: DateTime.utc_now,
         }
       end