27: Add pagination support (Elixir)

elixir/lib/cli.ex

@@ -1,7 +1,9 @@
 defmodule GithubRepoCloner.CLI do
+  alias GithubRepoCloner.Cloner
+  alias GithubRepoCloner.PageIterator
+
   def main(args \\ []) do
-    args
-    |> List.first
-    |> GithubRepoCloner.Cloner.clone
+    username = List.first(args)
+    PageIterator.repeat(&Cloner.clone_page/1, %{username: username, page: 1})
   end
 end

elixir/lib/cloner.ex

@@ -2,19 +2,18 @@ defmodule GithubRepoCloner.Cloner do
   @http_client Application.compile_env(:github_repo_cloner, :http_client)
   @system Application.compile_env(:github_repo_cloner, :system)
 
-  def clone(nil), do: true
+  def clone_page(%{username: nil}), do: {:error, "No repositories found"}
+  def clone_page(%{page: nil}), do: {:error, "No repositories found"}
 
-  def clone(username) do
+  def clone_page(%{username: username, page: page}) do
     username
-    |> request_repo_info
+    |> request_repo_info(page)
     |> parse_response
     |> clone_repos(username)
   end
 
-  def clone, do: true
-
-  defp request_repo_info(username) do
-    @http_client.get("https://api.github.com/users/#{username}/repos")
+  defp request_repo_info(username, page) do
+    @http_client.get("https://api.github.com/users/#{username}/repos?page=#{page}")
   end
 
   defp parse_response({:ok, %Tesla.Env{status: 200, body: body}}) do
@@ -30,7 +29,11 @@ defmodule GithubRepoCloner.Cloner do
     |> run_command
   end
 
+  defp run_command("") do
+    {:error, "No repositories found"}
+  end
+
   defp run_command(command) do
-    @system.cmd("sh", ["-c", command])
+    {:ok, @system.cmd("sh", ["-c", command])}
   end
 end

elixir/lib/page_iterator.ex

@@ -0,0 +1,12 @@
+defmodule GithubRepoCloner.PageIterator do
+  def repeat(function, arguments = %{page: page}) do
+    {status, _} = function.(%{arguments | page: page})
+    repeat(function, arguments, status)
+  end
+
+  def repeat(function, arguments = %{page: page}, :ok) do
+    repeat(function, %{arguments | page: page + 1})
+  end
+
+  def repeat(_function, %{page: page}, :error), do: {:ok, page}
+end

elixir/test/cloner_test.exs

@@ -3,8 +3,9 @@ defmodule GithubRepoCloner.ClonerTest do
   import Mox
   alias GithubRepoCloner.Cloner
 
-  test "clone\1: valid username with repos" do
+  test "clone_page\1: valid username with repos" do
     username = "murjax"
+    page = "2"
     clone_url1 = "https://github.com/murjax/spring_engine.git"
     clone_url2 = "https://github.com/murjax/burger_bot.git"
     name1 = "spring_engine"
@@ -24,26 +25,26 @@ defmodule GithubRepoCloner.ClonerTest do
         {:ok, %Tesla.Env{status: 200, body: serialized_repo_info}}
       end)
 
-    result = Cloner.clone(username)
+    {:ok, result} = Cloner.clone_page(%{username: username, page: page})
     assert ^result = expected_result
   end
 
-  test "clone\1: valid username without repos" do
+  test "clone_page\1: valid username without repos" do
     username = "murjax"
-    expected_result = {:ok, "Command executed: "}
+    page = "2"
 
     expect(
       GithubRepoCloner.Http.Mock, :get, fn _url ->
         {:ok, %Tesla.Env{status: 200, body: "[]"}}
       end)
 
-    result = Cloner.clone(username)
-    assert ^result = expected_result
+    {:error, result} = Cloner.clone_page(%{username: username, page: page})
+    assert ^result = "No repositories found"
   end
 
-  test "clone\1: username not found" do
+  test "clone_page\1: username not found" do
     username = "foo"
-    expected_result = {:ok, "Command executed: "}
+    page = "2"
     response_body = %{"message" => "Not Found"}
     {_, serialized_response_body} = Poison.encode(response_body)
 
@@ -52,17 +53,18 @@ defmodule GithubRepoCloner.ClonerTest do
         {:ok, %Tesla.Env{status: 404, body: serialized_response_body}}
       end)
 
-    result = Cloner.clone(username)
-    assert ^result = expected_result
+    {:error, result} = Cloner.clone_page(%{username: username, page: page})
+    assert ^result = "No repositories found"
   end
 
-  test "clone\1: nil" do
-    result = Cloner.clone(nil)
-    assert ^result = true
+  test "clone_page/1: nil username" do
+    {:error, result} = Cloner.clone_page(%{username: nil, page: nil})
+    assert ^result = "No repositories found"
   end
 
-  test "clone\0: valid noop" do
-    result = Cloner.clone
-    assert ^result = true
+  test "clone_page/1: nil page" do
+    username = "murjax"
+    {:error, result} = Cloner.clone_page(%{username: username, page: nil})
+    assert ^result = "No repositories found"
   end
 end

elixir/test/page_iterator_test.exs

@@ -0,0 +1,23 @@
+defmodule GithubRepoCloner.PageIteratorTest do
+  use ExUnit.Case
+  alias GithubRepoCloner.PageIterator
+
+  test "repeat/3: Repeat function with next page until it returns an error" do
+    {:ok, page_reached} = PageIterator.repeat(&TestIteratable.runner/1, %{username: "murjax", page: 1})
+    assert ^page_reached = 3
+  end
+end
+
+defmodule TestIteratable do
+  def runner(%{username: username, page: 1}) do
+    {:ok, username}
+  end
+
+  def runner(%{username: username, page: 2}) do
+    {:ok, username}
+  end
+
+  def runner(%{username: _, page: 3}) do
+    {:error, "Finished"}
+  end
+end