Fix incorrect matches for long namespaces when run in relative dir

When rubocop is run in a relative path to a spec with long
namespace, e.g. in the same directory, the FilePath spec will
return incorrect matches.

This fixes them by switching to a regular expression based pattern
matching which allows more specific matchign than the previously
used globs.

Adds new specs to ensure the file extension is matched against the
ruby file extension (.rb).

Fixes #1091

Author: ahukkanen

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 ## Master (Unreleased)
 
+* Fix `RSpec/FilePath` false positive for relative file path runs with long namespaces. ([@ahukkanen][])
+
 ## 2.0.1 (2020-12-02)
 
 * Fixed infinite loop in `RSpec/ExpectActual` autocorrection when both expected and actual values are literals. ([@Darhazer][])
@@ -590,3 +592,4 @@ Compatibility release so users can upgrade RuboCop to 0.51.0. No new features.
 [@Rafix02]: https://github.com/Rafix02
 [@PhilCoggins]: https://github.com/PhilCoggins
 [@sl4vr]: https://github.com/sl4vr
+[@ahukkanen]: https://github.com/ahukkanen

lib/rubocop/cop/rspec/file_path.rb

@@ -82,30 +82,39 @@ def on_top_level_example_group(node)
         private
 
         def ensure_correct_file_path(send_node, described_class, arguments)
-          glob = glob_for(described_class, arguments.first)
-          return if filename_ends_with?(glob)
-
-          add_offense(send_node, message: format(MSG, suffix: glob))
+          pattern = pattern_for(described_class, arguments.first)
+          return if filename_ends_with?(pattern)
+
+          # For the suffix shown in the offense message, modify the regular
+          # expression pattern to resemble a glob pattern for clearer error
+          # messages.
+          offense_suffix = pattern.gsub('.*', '*').sub('[^/]', '')
+            .sub('\.', '.')
+          add_offense(send_node, message: format(MSG, suffix: offense_suffix))
         end
 
         def routing_spec?(args)
           args.any?(&method(:routing_metadata?))
         end
 
-        def glob_for(described_class, method_name)
-          return glob_for_spec_suffix_only? if spec_suffix_only?
+        def pattern_for(described_class, method_name)
+          return pattern_for_spec_suffix_only? if spec_suffix_only?
 
-          "#{expected_path(described_class)}#{name_glob(method_name)}*_spec.rb"
+          [
+            expected_path(described_class),
+            name_pattern(method_name),
+            '[^/]*_spec\.rb'
+          ].join
         end
 
-        def glob_for_spec_suffix_only?
-          '*_spec.rb'
+        def pattern_for_spec_suffix_only?
+          '.*_spec\.rb'
         end
 
-        def name_glob(method_name)
+        def name_pattern(method_name)
           return unless method_name&.str_type?
 
-          "*#{method_name.str_content.gsub(/\W/, '')}" unless ignore_methods?
+          ".*#{method_name.str_content.gsub(/\W/, '')}" unless ignore_methods?
         end
 
         def expected_path(constant)
@@ -131,11 +140,9 @@ def ignore_methods?
           cop_config['IgnoreMethods']
         end
 
-        def filename_ends_with?(glob)
-          filename =
-            RuboCop::PathUtil.relative_path(processed_source.buffer.name)
-              .gsub('../', '')
-          File.fnmatch?("*#{glob}", filename)
+        def filename_ends_with?(pattern)
+          filename = File.expand_path(processed_source.buffer.name)
+          filename.match?("#{pattern}$")
         end
 
         def relevant_rubocop_rspec_file?(_file)

spec/rubocop/cop/rspec/file_path_spec.rb

@@ -64,6 +64,13 @@
     RUBY
   end
 
+  it 'registers an offense for a file without the .rb extension' do
+    expect_offense(<<-RUBY, 'spec/models/user_specxrb')
+      describe User do; end
+      ^^^^^^^^^^^^^ Spec path should end with `user*_spec.rb`.
+    RUBY
+  end
+
   it 'ignores shared examples' do
     expect_no_offenses(<<-RUBY, 'spec/models/user.rb')
       shared_examples_for 'foo' do; end
@@ -183,30 +190,26 @@
     RUBY
   end
 
-  it 'uses relative path' do
-    allow(RuboCop::PathUtil)
-      .to receive(:relative_path).and_return('spec/models/bar_spec.rb')
+  it 'registers an offense for a path containing the class name' do
     expect_offense(<<-RUBY, '/home/foo/spec/models/bar_spec.rb')
       describe Foo do; end
       ^^^^^^^^^^^^ Spec path should end with `foo*_spec.rb`.
     RUBY
   end
 
-  it 'uses relative path for sibling directory project' do
-    allow(RuboCop::PathUtil)
-      .to receive(:relative_path)
-      .and_return('../ext-project/spec/models/bar_spec.rb')
-    expect_no_offenses(<<-RUBY, '/home/ext-project/spec/models/bar_spec.rb')
-      describe Bar do; end
+  it 'detects the path based on a class name with long module' do
+    expect_offense(<<-RUBY, '/home/foo/spec/very/my_class_spec.rb')
+      describe Very::Long::Namespace::MyClass do; end
+      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Spec path should end with `very/long/namespace/my_class*_spec.rb`.
     RUBY
   end
 
-  it 'uses relative path for different path project' do
-    allow(RuboCop::PathUtil)
-      .to receive(:relative_path)
-      .and_return('../../opt/ext-project/spec/models/bar_spec.rb')
-    expect_no_offenses(<<-RUBY, '/opt/ext-project/spec/models/bar_spec.rb')
-      describe Bar do; end
+  it 'detects the path based the absolute path of the file' do
+    allow(File).to receive(:expand_path).with('my_class_spec.rb').and_return(
+      '/home/foo/spec/very/long/namespace/my_class_spec.rb'
+    )
+    expect_no_offenses(<<-RUBY, 'my_class_spec.rb')
+      describe Very::Long::Namespace::MyClass do; end
     RUBY
   end
 
@@ -259,5 +262,12 @@ class Foo
         ^^^^^^^^^^^^^^^^ Spec path should end with `*_spec.rb`.
       RUBY
     end
+
+    it 'registers an offense when the file extension is not .rb' do
+      expect_offense(<<-RUBY, 'whatever_specxrb')
+        describe MyClass do; end
+        ^^^^^^^^^^^^^^^^ Spec path should end with `*_spec.rb`.
+      RUBY
+    end
   end
 end