Add Lint/SpecFilename rule

spec/ameba/rule/lint/spec_filename_spec.cr

@@ -0,0 +1,36 @@
+require "../../../spec_helper"
+
+module Ameba::Rule::Lint
+  subject = SpecFilename.new
+
+  describe SpecFilename do
+    it "passes if filename is correct" do
+      expect_no_issues subject, code: "", path: "spec/foo_spec.cr"
+      expect_no_issues subject, code: "", path: "spec/foo/bar_spec.cr"
+    end
+
+    it "fails if filename is wrong" do
+      expect_issue subject, <<-CRYSTAL, path: "spec/foo.cr"
+
+        # ^{} error: Spec filename should have `_spec` suffix: foo_spec.cr, not foo.cr
+        CRYSTAL
+    end
+
+    context "properties" do
+      context "#ignored_dirs" do
+        it "provide sane defaults" do
+          expect_no_issues subject, code: "", path: "spec/support/foo.cr"
+          expect_no_issues subject, code: "", path: "spec/fixtures/foo.cr"
+          expect_no_issues subject, code: "", path: "spec/data/foo.cr"
+        end
+      end
+
+      context "#ignored_filenames" do
+        it "ignores spec_helper by default" do
+          expect_no_issues subject, code: "", path: "spec/spec_helper.cr"
+          expect_no_issues subject, code: "", path: "spec/foo/spec_helper.cr"
+        end
+      end
+    end
+  end
+end

src/ameba/rule/lint/spec_filename.cr

@@ -0,0 +1,50 @@
+require "file_utils"
+
+module Ameba::Rule::Lint
+  # A rule that enforces spec filenames to have `_spec` suffix.
+  #
+  # YAML configuration example:
+  #
+  # ```
+  # Lint/SpecFilename:
+  #   Enabled: true
+  # ```
+  class SpecFilename < Base
+    properties do
+      description "Enforces spec filenames to have `_spec` suffix"
+      ignored_dirs %w[spec/support spec/fixtures spec/data]
+      ignored_filenames %w[spec_helper]
+    end
+
+    MSG = "Spec filename should have `_spec` suffix: %s.cr, not %s.cr"
+
+    private LOCATION = {1, 1}
+
+    # TODO: fix the assumption that *source.path* contains relative path
+    def test(source : Source)
+      path_ = Path[source.path].to_posix
+      name = path_.stem
+      path = path_.to_s
+
+      # check files only within spec/ directory
+      return unless path.starts_with?("spec/")
+      # ignore files having `_spec` suffix
+      return if name.ends_with?("_spec")
+
+      # ignore known false-positives
+      ignored_dirs.each do |substr|
+        return if path.starts_with?("#{substr}/")
+      end
+      return if name.in?(ignored_filenames)
+
+      expected = "#{name}_spec"
+
+      issue_for LOCATION, MSG % {expected, name} do
+        new_path =
+          path_.sibling(expected + path_.extension)
+
+        FileUtils.mv(path, new_path)
+      end
+    end
+  end
+end