From 759a1f8103e9557ee5f20ee35f6101ec941b7b5c Mon Sep 17 00:00:00 2001
From: Baron Bloomer <baronbloomer@gmail.com>
Date: Tue, 22 Nov 2022 11:18:00 +0000
Subject: [PATCH] Raise error if provided file path cannot be found

This will help developers debug issues related to an incorrect file path as early as possible.
---
 lib/data_migrate.rb                                |  2 +-
 lib/data_migrate/config.rb                         |  6 ++++++
 spec/data_migrate/config_spec.rb                   | 14 +++++++++++++-
 .../data_migration_generator_spec.rb               |  8 +++++---
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/lib/data_migrate.rb b/lib/data_migrate.rb
index 5820e5c9..39ce3a88 100644
--- a/lib/data_migrate.rb
+++ b/lib/data_migrate.rb
@@ -20,6 +20,6 @@
 
 module DataMigrate
   def self.root
-    File.dirname(__dir__)
+    File.dirname(__FILE__)
   end
 end
diff --git a/lib/data_migrate/config.rb b/lib/data_migrate/config.rb
index 426ec409..a7aff17a 100644
--- a/lib/data_migrate/config.rb
+++ b/lib/data_migrate/config.rb
@@ -22,5 +22,11 @@ def initialize
       @db_configuration = nil
       @spec_name = nil
     end
+
+    def data_template_path=(value)
+      @data_template_path = value.tap do |path|
+        raise ArgumentError, "File not found: '#{path}'" unless path == DEFAULT_DATA_TEMPLATE_PATH || File.exists?(path)
+      end
+    end
   end
 end
diff --git a/spec/data_migrate/config_spec.rb b/spec/data_migrate/config_spec.rb
index 6f264bfc..60cd0db9 100644
--- a/spec/data_migrate/config_spec.rb
+++ b/spec/data_migrate/config_spec.rb
@@ -39,7 +39,9 @@
       end
     end
 
-    let(:data_template_path) { "lib/awesome/templates/data_migration.rb" }
+    let(:data_template_path) do
+      File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb")
+    end
 
     after do
       DataMigrate.configure do |config|
@@ -50,5 +52,15 @@
     it "equals the custom data template path" do
       is_expected.to eq data_template_path
     end
+
+    context "when path does not exist" do
+      subject { DataMigrate.config.data_template_path = invalid_path }
+
+      let(:invalid_path) { "lib/awesome/templates/data_migration.rb" }
+
+      it "checks that file exists on setting config var" do
+        expect { subject }.to raise_error { ArgumentError.new("File not found: '#{data_template_path}'") }
+      end
+    end
   end
 end
diff --git a/spec/generators/data_migration/data_migration_generator_spec.rb b/spec/generators/data_migration/data_migration_generator_spec.rb
index 26a92a3d..47547154 100644
--- a/spec/generators/data_migration/data_migration_generator_spec.rb
+++ b/spec/generators/data_migration/data_migration_generator_spec.rb
@@ -68,7 +68,7 @@
 
     let(:default_source_root) do
       File.expand_path(
-        File.dirname(File.join(DataMigrate.root, "lib", "generators", "data_migration", "templates", "data_migration.rb"))
+        File.dirname(File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb"))
       )
     end
 
@@ -82,8 +82,10 @@
         end
       end
 
-      let(:data_template_path) { "lib/awesome/templates/data_migration.rb" }
-      let(:expected_source_root) { File.expand_path(File.dirname(File.join(DataMigrate.root, data_template_path))) }
+      let(:data_template_path) do
+        File.join(DataMigrate.root, "generators", "data_migration", "templates", "data_migration.rb")
+      end
+      let(:expected_source_root) { File.dirname(data_template_path) }
 
       after do
         DataMigrate.configure do |config|