Fix #867

lib/credo/check/readability/predicate_function_names.ex

@@ -81,6 +81,9 @@ defmodule Credo.Check.Readability.PredicateFunctionNames do
       {name, meta, nil} ->
         issues_for_name(op, name, meta, issues, issue_meta)
 
+      {name, meta, [_|_]} ->
+        issues_for_name(op, name, meta, issues, issue_meta)
+
       _ ->
         issues
     end

test/credo/check/readability/predicate_function_names_test.exs

@@ -19,6 +19,18 @@ defmodule Credo.Check.Readability.PredicateFunctionNamesTest do
     |> refute_issues()
   end
 
+  test "it should NOT report expected code with arity on function" do
+    """
+    def valid?(a) do
+    end
+    defp has_attachment?(a) do
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check)
+    |> refute_issues()
+  end
+
   #
   # cases raising issues
   #
@@ -44,4 +56,24 @@ defmodule Credo.Check.Readability.PredicateFunctionNamesTest do
     |> run_check(@described_check)
     |> assert_issues()
   end
+
+  test "it should report a violation with arity" do
+    """
+    def is_valid?(a) do
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check)
+    |> assert_issue()
+  end
+
+  test "it should report a violation with arity /2" do
+    """
+    def is_valid(a) do
+    end
+    """
+    |> to_source_file
+    |> run_check(@described_check)
+    |> assert_issue()
+  end
 end