Refactor modules into contexts (#78)

* [WIP] break out a few contexts, start refactoring fast index modules

* [WIP] more contexts, this time around slow indexing and downloads

* [WIP] got all tests passing

* [WIP] Added moduledocs

* Built a genserver to rename old jobs on boot

* Added a module naming check; moved things around

* Fixed specs

test/pinchflat/slow_indexing/file_follower_server_test.exs

@@ -0,0 +1,52 @@
+defmodule Pinchflat.SlowIndexing.FileFollowerServerTest do
+  use ExUnit.Case, async: true
+
+  alias alias Pinchflat.Filesystem.FilesystemHelpers
+  alias Pinchflat.SlowIndexing.FileFollowerServer
+
+  setup do
+    {:ok, pid} = FileFollowerServer.start_link()
+    tmpfile = FilesystemHelpers.generate_metadata_tmpfile(:txt)
+
+    {:ok, %{pid: pid, tmpfile: tmpfile}}
+  end
+
+  describe "watch_file" do
+    test "calls the handler for each existing line in the file", %{pid: pid, tmpfile: tmpfile} do
+      File.write!(tmpfile, "line1\nline2")
+      parent = self()
+
+      handler = fn line -> send(parent, line) end
+      FileFollowerServer.watch_file(pid, tmpfile, handler)
+
+      assert_receive "line1\n"
+      assert_receive "line2"
+    end
+
+    test "calls the handler for each new line in the file", %{pid: pid, tmpfile: tmpfile} do
+      parent = self()
+      file = File.open!(tmpfile, [:append])
+      handler = fn line -> send(parent, line) end
+
+      FileFollowerServer.watch_file(pid, tmpfile, handler)
+
+      IO.binwrite(file, "line1\n")
+      assert_receive "line1\n"
+      IO.binwrite(file, "line2")
+      assert_receive "line2"
+    end
+  end
+
+  describe "stop" do
+    test "stops the watcher", %{pid: pid, tmpfile: tmpfile} do
+      handler = fn _line -> :noop end
+      FileFollowerServer.watch_file(pid, tmpfile, handler)
+
+      refute is_nil(Process.info(pid))
+      FileFollowerServer.stop(pid)
+      # Gotta wait for the server to stop async
+      :timer.sleep(50)
+      assert is_nil(Process.info(pid))
+    end
+  end
+end