Add settings model (#54)

* Adds a basic settings model

* Added more settings methods; Hooked up initial settings runner to app boot

* Update onboarding flow to use settings model instead of session data

test/pinchflat/settings_test.exs

@@ -0,0 +1,108 @@
+defmodule Pinchflat.SettingsTest do
+  use Pinchflat.DataCase
+
+  alias Pinchflat.Settings
+  alias Pinchflat.Settings.Setting
+
+  # NOTE: We're treating some of these tests differently
+  # than in other modules because certain settings
+  # are always created on app boot (including in the test env),
+  # so we can't treat these like a clean slate.
+
+  describe "list_settings/0" do
+    test "returns all settings" do
+      Settings.set!("foo", "bar")
+      results = Settings.list_settings()
+
+      assert Enum.all?(results, fn setting -> match?(%Setting{}, setting) end)
+    end
+  end
+
+  describe "set/2" do
+    test "creates a new setting if one does not exist" do
+      original = Repo.aggregate(Setting, :count, :id)
+      Settings.set!("foo", "bar")
+      assert Repo.aggregate(Setting, :count, :id) == original + 1
+    end
+
+    test "updates an existing setting if one exists" do
+      Settings.set!("foo", "bar")
+      original = Repo.aggregate(Setting, :count, :id)
+      Settings.set!("foo", "baz")
+      assert Repo.aggregate(Setting, :count, :id) == original
+      assert Settings.get!("foo") == "baz"
+    end
+
+    test "returns the parsed value" do
+      assert Settings.set!("foo", true) == true
+      assert Settings.set!("foo", false) == false
+      assert Settings.set!("foo", 123) == 123
+      assert Settings.set!("foo", 12.34) == 12.34
+      assert Settings.set!("foo", "bar") == "bar"
+    end
+
+    test "allows for atom keys" do
+      assert Settings.set!(:foo, "bar") == "bar"
+    end
+
+    test "blows up when an unsupported datatype is used" do
+      assert_raise FunctionClauseError, fn ->
+        Settings.set!("foo", nil)
+      end
+    end
+  end
+
+  describe "set/3" do
+    test "allows manual specification of datatype" do
+      assert Settings.set!("foo", "true", :boolean) == true
+      assert Settings.set!("foo", "false", :boolean) == false
+      assert Settings.set!("foo", "123", :integer) == 123
+      assert Settings.set!("foo", "12.34", :float) == 12.34
+    end
+  end
+
+  describe "get/1" do
+    test "returns the value of the setting" do
+      Settings.set!("str", "bar")
+      Settings.set!("bool", true)
+      Settings.set!("int", 123)
+      Settings.set!("float", 12.34)
+
+      assert Settings.get!("str") == "bar"
+      assert Settings.get!("bool") == true
+      assert Settings.get!("int") == 123
+      assert Settings.get!("float") == 12.34
+    end
+
+    test "allows for atom keys" do
+      Settings.set!("str", "bar")
+      assert Settings.get!(:str) == "bar"
+    end
+
+    test "blows up when the setting does not exist" do
+      assert_raise Ecto.NoResultsError, fn ->
+        Settings.get!("foo")
+      end
+    end
+  end
+
+  describe "fetch/2" do
+    test "creates a setting if one doesn't exist" do
+      original = Repo.aggregate(Setting, :count, :id)
+      assert Settings.fetch!("foo", "bar") == "bar"
+      assert Repo.aggregate(Setting, :count, :id) == original + 1
+    end
+
+    test "returns an existing setting if one does exist" do
+      Settings.set!("foo", "bar")
+
+      assert Settings.fetch!("foo", "baz") == "bar"
+    end
+  end
+
+  describe "fetch/3" do
+    test "allows manual specification of datatype" do
+      assert Settings.fetch!("foo", "true", :boolean) == true
+    end
+  end
+end