Do load .env.local in Rails' test environment

This basically reverts bkeepers#280.

The above-mentioned PR says:

> When using .env.local for tests, the tests are not transparent and
> can't be executed for example on a CI server.
> As the documentation says, the .env.local is here for local
> overwrites. They should not overwrite a test specific variable. Tests
> should be run on every machine in every environment and shouldn't
> require any specification of environment variables.

While that description matches the expected behavior of Dotenv, the
implementation goes too far (1) and even contradicts other bits of Dotenv's
current behavior (2).

About (1), a [quote][jakedouglas-comment] from the Github user named jakedouglas:

>> Tests should be run on every machine in every environment and
>> shouldn't require any specification of environment variables.
>
> At least one very common example of this idea not holding water is
> that most Rails applications require a database, and the URL of that
> database may vary between different developer machines, and between
> developer machines and a CI service. Given this PR, if a developer
> happens to have a database setup that doesn't match the
> application's defaults (common), they need to specify the database
> URL in both .env.local and .env.test.local in order to do local
> development comprehensively.

About (2), anything that .env.local could do to the test environment
variables before it became ignored for that environment can now be done
with .env.test.local, often at the cost of tediously duplicating
variables from the currently-ignored .env.local. This contradicts the
behavior intended by PR bkeepers#280 and consistency would dictate that
.env.test.local be removed altogether. Only then the test variables
would truly be guaranteed to always stay the same as far as Dotenv is
concerned.

Since (1) shows that local development might require local test
variables for legitimate reasons, removing .env.test.local is not a
valid option and it would make sense to instead restore loading
.env.local for the test environment.

[jakedouglas-comment]: bkeepers#280 (comment)

README.md

@@ -207,7 +207,7 @@ If you use this gem to handle env vars for multiple Rails environments (developm
 | 1st (highest)      | `.env.development.local` | Development          | Yes!                                                | Local overrides of environment-specific settings.            |
 | 1st                | `.env.test.local`        | Test                 | Yes!                                                | Local overrides of environment-specific settings.            |
 | 1st                | `.env.production.local`  | Production           | Yes!                                                | Local overrides of environment-specific settings.            |
-| 2nd                | `.env.local`             | Wherever the file is | Definitely.                                         | Local overrides. This file is loaded for all environments _except_ `test`. |
+| 2nd                | `.env.local`             | Wherever the file is | Definitely.                                         | Local overrides. This file is loaded for all environments.   |
 | 3rd                | `.env.development`       | Development          | No.                                                 | Shared environment-specific settings                         |
 | 3rd                | `.env.test`              | Test                 | No.                                                 | Shared environment-specific settings                         |
 | 3rd                | `.env.production`        | Production           | No.                                                 | Shared environment-specific settings                         |

lib/dotenv/rails.rb

@@ -66,7 +66,7 @@ def self.load
     def dotenv_files
       [
         root.join(".env.#{Rails.env}.local"),
-        (root.join(".env.local") unless Rails.env.test?),
+        root.join(".env.local"),
         root.join(".env.#{Rails.env}"),
         root.join(".env")
       ].compact

spec/dotenv/rails_spec.rb

@@ -50,17 +50,18 @@ def add(*items)
       expect(Spring.watcher.items).to include(path)
     end
 
-    it "does not load .env.local in test rails environment" do
+    it "loads .env.local in test rails environment" do
       expect(Dotenv::Railtie.instance.send(:dotenv_files)).to eql(
         [
           Rails.root.join(".env.test.local"),
+          Rails.root.join(".env.local"),
           Rails.root.join(".env.test"),
           Rails.root.join(".env")
         ]
       )
     end
 
-    it "does load .env.local in development environment" do
+    it "loads .env.local in development environment" do
       Rails.env = "development"
       expect(Dotenv::Railtie.instance.send(:dotenv_files)).to eql(
         [
@@ -72,8 +73,8 @@ def add(*items)
       )
     end
 
-    it "loads .env.test before .env" do
-      expect(ENV["DOTENV"]).to eql("test")
+    it "loads .env.local before .env" do
+      expect(ENV["DOTENV"]).to eql("local")
     end
 
     context "when Rails.root is nil" do
@@ -91,17 +92,18 @@ def add(*items)
   context "overload" do
     before { Dotenv::Railtie.overload }
 
-    it "does not load .env.local in test rails environment" do
+    it "loads .env.local in test rails environment" do
       expect(Dotenv::Railtie.instance.send(:dotenv_files)).to eql(
         [
           Rails.root.join(".env.test.local"),
+          Rails.root.join(".env.local"),
           Rails.root.join(".env.test"),
           Rails.root.join(".env")
         ]
       )
     end
 
-    it "does load .env.local in development environment" do
+    it "loads .env.local in development environment" do
       Rails.env = "development"
       expect(Dotenv::Railtie.instance.send(:dotenv_files)).to eql(
         [
@@ -113,7 +115,7 @@ def add(*items)
       )
     end
 
-    it "overloads .env.test with .env" do
+    it "overloads .env.local with .env" do
       expect(ENV["DOTENV"]).to eql("true")
     end