diff --git a/lib/credo/check/runner.ex b/lib/credo/check/runner.ex
index e44388d0b..e6f94f2b9 100644
--- a/lib/credo/check/runner.ex
+++ b/lib/credo/check/runner.ex
@@ -61,6 +61,10 @@ defmodule Credo.Check.Runner do
           exec
           |> Execution.working_dir()
           |> Credo.Sources.find_in_dir(files_included, files_excluded)
+          |> case do
+            [] -> :skip_run
+            files -> files
+          end
       end
 
     source_files =
diff --git a/lib/credo/check/warning/wrong_test_file_extension.ex b/lib/credo/check/warning/wrong_test_file_extension.ex
index b90ee7ded..d680e4a0f 100644
--- a/lib/credo/check/warning/wrong_test_file_extension.ex
+++ b/lib/credo/check/warning/wrong_test_file_extension.ex
@@ -3,7 +3,7 @@ defmodule Credo.Check.Warning.WrongTestFileExtension do
     id: "EX5025",
     base_priority: :high,
     param_defaults: [
-      files: %{included: ["test/**/*_test.exs"]}
+      files: %{included: ["test/**/*_test.ex"]}
     ],
     explanations: [
       check: """
@@ -12,7 +12,7 @@ defmodule Credo.Check.Warning.WrongTestFileExtension do
 
       (from the `ex_unit` docs)
 
-      This check ensures that test files are not ending with `.ex` (which would cause them to be skipped).
+      This check ensures that test files are not ending with `_test.ex` (which would cause them to be skipped).
       """
     ]