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/downloading/output_path/parser_test.exs

@@ -0,0 +1,48 @@
+defmodule Pinchflat.Downloading.OutputPath.ParserTest do
+  use ExUnit.Case, async: true
+
+  alias Pinchflat.Downloading.OutputPath.Parser
+
+  describe "parse/3" do
+    test "it returns the rendered string when the string is valid" do
+      assert {:ok, "bar"} = Parser.parse("{{ foo }}", %{"foo" => "bar"})
+    end
+
+    test "it works with filepath-like strings" do
+      assert {:ok, "bar/baz"} =
+               Parser.parse("{{ foo }}/{{ bar }}", %{"foo" => "bar", "bar" => "baz"})
+    end
+
+    test "it works when mixing text and variables" do
+      assert {:ok, "bar text baz"} =
+               Parser.parse("{{ foo }} text {{ bar }}", %{"foo" => "bar", "bar" => "baz"})
+    end
+
+    test "it removes the placeholder but doesn't blow up when the variable isn't provided" do
+      assert {:ok, ""} = Parser.parse("{{ foo }}", %{})
+    end
+
+    test "it accepts any number of spaces between open and closing tags" do
+      assert {:ok, "bar"} = Parser.parse("{{foo}}", %{"foo" => "bar"})
+      assert {:ok, "bar"} = Parser.parse("{{ foo}}", %{"foo" => "bar"})
+      assert {:ok, "bar"} = Parser.parse("{{foo }}", %{"foo" => "bar"})
+      assert {:ok, "bar"} = Parser.parse("{{   foo   }}", %{"foo" => "bar"})
+    end
+
+    test "it doesn't interpret single braces as variables" do
+      assert {:ok, "{foo}"} = Parser.parse("{foo}", %{})
+    end
+
+    test "it returns an error when the string is invalid" do
+      assert {:error, "expected end of string"} = Parser.parse("{{ 1-1 }", %{})
+    end
+
+    test "it supports a custom fetcher function" do
+      custom_fetcher = fn _, _ ->
+        "quux"
+      end
+
+      assert {:ok, "quux"} = Parser.parse("{{ foo }}", %{}, custom_fetcher)
+    end
+  end
+end