Generate preview at overriden path if one exists when using --preview flag

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## main
 
+* Generate preview at overridden path if one exists when using `--preview` flag.
+
+    *Nishiki Liu*
+
 ## 2.26.1
 
 * Fix bug that raises when trying to use a collection before the component has been compiled.

docs/index.md

@@ -1248,3 +1248,8 @@ ViewComponent is built by:
 |:---:|:---:|:---:|:---:|:---:|
 |@mixergtz|@jules2689|@g13ydson|@swanson|@bobmaerten|
 |Medellin, Colombia|Toronto, Canada|João Pessoa, Brazil|Indianapolis, IN|Valenciennes, France|
+
+|<img src="https://avatars.githubusercontent.com/nshki?s=256" alt="nshki" width="128" />|
+|:---:|
+|@nshki|
+|Los Angeles, CA|

lib/rails/generators/preview/component_generator.rb

@@ -8,7 +8,11 @@ class ComponentGenerator < ::Rails::Generators::NamedBase
       check_class_collision suffix: "ComponentPreview"
 
       def create_preview_file
-        template "component_preview.rb", File.join("test/components/previews", class_path, "#{file_name}_component_preview.rb")
+        preview_paths = Rails.application.config.view_component.preview_paths
+        return if preview_paths.count > 1
+
+        path_prefix = preview_paths.one? ? preview_paths.first : "test/components/previews"
+        template "component_preview.rb", File.join(path_prefix, class_path, "#{file_name}_component_preview.rb")
       end
 
       private

test/generators/component_generator_test.rb

@@ -32,11 +32,34 @@ def test_component_tests
   end
 
   def test_component_preview
-    run_generator %w[user --preview]
+    with_preview_paths([]) do
+      run_generator %w[user --preview]
 
-    assert_file "test/components/previews/user_component_preview.rb" do |component|
-      assert_match(/class UserComponentPreview < /, component)
-      assert_match(/render\(UserComponent.new\)/, component)
+      assert_file "test/components/previews/user_component_preview.rb" do |component|
+        assert_match(/class UserComponentPreview < /, component)
+        assert_match(/render\(UserComponent.new\)/, component)
+      end
+    end
+  end
+
+  def test_component_preview_with_one_overridden_preview_path
+    with_preview_paths(%w[spec/components/previews]) do
+      run_generator %w[user --preview]
+
+      assert_file "spec/components/previews/user_component_preview.rb" do |component|
+        assert_match(/class UserComponentPreview < /, component)
+        assert_match(/render\(UserComponent.new\)/, component)
+      end
+    end
+  end
+
+  def test_component_preview_with_two_overridden_preview_paths
+    with_preview_paths(%w[spec/components/previews some/other/directory]) do
+      run_generator %w[user --preview]
+
+      assert_no_file "test/components/previews/user_component_preview.rb"
+      assert_no_file "spec/components/previews/user_component_preview.rb"
+      assert_no_file "some/other/directory/user_component_preview.rb"
     end
   end
 
@@ -76,11 +99,13 @@ def test_component_tests_with_namespace
   end
 
   def test_component_preview_with_namespace
-    run_generator %w[admins/user --preview]
+    with_preview_paths([]) do
+      run_generator %w[admins/user --preview]
 
-    assert_file "test/components/previews/admins/user_component_preview.rb" do |component|
-      assert_match(/class Admins::UserComponentPreview < /, component)
-      assert_match(/render\(Admins::UserComponent.new\)/, component)
+      assert_file "test/components/previews/admins/user_component_preview.rb" do |component|
+        assert_match(/class Admins::UserComponentPreview < /, component)
+        assert_match(/render\(Admins::UserComponent.new\)/, component)
+      end
     end
   end
 

test/test_helper.rb

@@ -21,6 +21,18 @@
 require File.expand_path("../config/environment.rb", __FILE__)
 require "rails/test_help"
 
+# Sets custom preview paths in tests.
+#
+# @param new_value [Array<String>] List of preview paths
+# @yield Test code to run
+# @return [void]
+def with_preview_paths(new_value)
+  old_value = Rails.application.config.view_component.preview_paths
+  Rails.application.config.view_component.preview_paths = new_value
+  yield
+  Rails.application.config.view_component.preview_paths = old_value
+end
+
 def with_preview_route(new_value)
   old_value = Rails.application.config.view_component.preview_route
   Rails.application.config.view_component.preview_route = new_value