Add database setup feature spec

spec/features/database_setup_spec.rb

@@ -0,0 +1,97 @@
+RSpec.describe "Setting up a database in a target gem", :with_gem do
+  context "when no database adaptor is set" do
+    before do
+      gem.main_file.write(<<~RUBY)
+        require "kangaru"
+
+        module SomeGem
+          extend Kangaru::Initialiser
+
+          Kangaru.application.configure do |config|
+          end
+        end
+      RUBY
+    end
+
+    it "does not raise any errors" do
+      expect { gem.load! }.not_to raise_error
+    end
+
+    it "does not setup a database" do
+      gem.load!
+      expect(Kangaru.application.database).to be_nil
+    end
+  end
+
+  context "when an invalid database adaptor is set" do
+    before do
+      gem.main_file.write(<<~RUBY)
+        require "kangaru"
+
+        module SomeGem
+          extend Kangaru::Initialiser
+
+          Kangaru.application.configure do |config|
+            config.database.adaptor = :invalid
+          end
+        end
+      RUBY
+    end
+
+    it "raises an error" do
+      expect { gem.load! }.to raise_error(
+        Kangaru::Database::AdaptorError, "invalid adaptor 'invalid'"
+      )
+    end
+  end
+
+  context "when adaptor is set to sqlite" do
+    context "and database path is not set" do
+      before do
+        gem.main_file.write(<<~RUBY)
+          require "kangaru"
+
+          module SomeGem
+            extend Kangaru::Initialiser
+
+            Kangaru.application.configure do |config|
+              config.database.adaptor = :sqlite
+            end
+          end
+        RUBY
+      end
+
+      it "raises an error" do
+        expect { gem.load! }.to raise_error(
+          Kangaru::Database::SQLiteError, "path can't be blank"
+        )
+      end
+    end
+
+    context "and database path is set" do
+      before do
+        gem.main_file.write(<<~RUBY)
+          require "kangaru"
+
+          module SomeGem
+            extend Kangaru::Initialiser
+
+            Kangaru.application.configure do |config|
+              config.database.adaptor = :sqlite
+              config.database.path    = "#{gem.path.join('database.sqlite3')}"
+            end
+          end
+        RUBY
+      end
+
+      it "does not raise any errors" do
+        expect { gem.load! }.not_to raise_error
+      end
+
+      it "sets the database instance" do
+        gem.load!
+        expect(Kangaru.application.database).to be_a(Kangaru::Database)
+      end
+    end
+  end
+end