diff --git a/spec/ameba/config_spec.cr b/spec/ameba/config_spec.cr
index d738310f..1c1d10b2 100644
--- a/spec/ameba/config_spec.cr
+++ b/spec/ameba/config_spec.cr
@@ -2,7 +2,7 @@ require "../spec_helper"
 
 module Ameba
   describe Config do
-    config_sample = "config/ameba.yml"
+    config_sample = "spec/fixtures/config.yml"
 
     it "should have a list of available formatters" do
       Config::AVAILABLE_FORMATTERS.should_not be_nil
@@ -84,6 +84,12 @@ module Ameba
         config.formatter.should_not be_nil
       end
 
+      it "raises when custom config file doesn't exist" do
+        expect_raises(Exception, "Unable to load config file: Config file does not exist foo.yml") do
+          Config.load "foo.yml"
+        end
+      end
+
       it "loads default config" do
         config = Config.load
         config.should_not be_nil
diff --git a/src/ameba/config.cr b/src/ameba/config.cr
index 3d3a3c71..821fa065 100644
--- a/src/ameba/config.cr
+++ b/src/ameba/config.cr
@@ -115,12 +115,13 @@ class Ameba::Config
               end
     Config.new YAML.parse(content)
   rescue e
-    raise "Config file is invalid: #{e.message}"
+    raise "Unable to load config file: #{e.message}"
   end
 
   protected def self.read_config(path = nil)
     if path
-      return File.exists?(path) ? File.read(path) : nil
+      raise ArgumentError.new("Config file does not exist #{path}") unless File.exists?(path)
+      return File.read(path)
     end
     each_config_path do |config_path|
       return File.read(config_path) if File.exists?(config_path)