diff --git a/spec/ameba/cli/cmd_spec.cr b/spec/ameba/cli/cmd_spec.cr
index f02707ea..c0206848 100644
--- a/spec/ameba/cli/cmd_spec.cr
+++ b/spec/ameba/cli/cmd_spec.cr
@@ -5,7 +5,7 @@ module Ameba::Cli
   describe "Cmd" do
     describe ".run" do
       it "runs ameba" do
-        r = Cli.run %w[-f silent -c spec/fixtures/config.yml spec/fixtures/source.cr]
+        r = Cli.run %w[-f silent file.cr]
         r.should be_nil
       end
     end
@@ -43,12 +43,12 @@ module Ameba::Cli
       end
 
       it "defaults rules? flag to false" do
-        c = Cli.parse_args %w[spec/fixtures/source.cr]
+        c = Cli.parse_args %w[file.cr]
         c.rules?.should be_false
       end
 
       it "defaults skip_reading_config? flag to false" do
-        c = Cli.parse_args %w[spec/fixtures/source.cr]
+        c = Cli.parse_args %w[file.cr]
         c.skip_reading_config?.should be_false
       end
 
@@ -58,7 +58,7 @@ module Ameba::Cli
       end
 
       it "defaults all? flag to false" do
-        c = Cli.parse_args %w[spec/fixtures/source.cr]
+        c = Cli.parse_args %w[file.cr]
         c.all?.should be_false
       end
 
@@ -95,35 +95,35 @@ module Ameba::Cli
 
       describe "-e/--explain" do
         it "configures file/line/column" do
-          c = Cli.parse_args %w[--explain spec/fixtures/source.cr:3:5]
+          c = Cli.parse_args %w[--explain src/file.cr:3:5]
 
           location_to_explain = c.location_to_explain.should_not be_nil
-          location_to_explain[:file].should eq "spec/fixtures/source.cr"
+          location_to_explain[:file].should eq "src/file.cr"
           location_to_explain[:line].should eq 3
           location_to_explain[:column].should eq 5
         end
 
         it "raises an error if location is not valid" do
           expect_raises(Exception, "location should have PATH:line:column") do
-            Cli.parse_args %w[--explain spec/fixtures/source.cr:3]
+            Cli.parse_args %w[--explain src/file.cr:3]
           end
         end
 
         it "raises an error if line number is not valid" do
           expect_raises(Exception, "location should have PATH:line:column") do
-            Cli.parse_args %w[--explain spec/fixtures/source.cr:a:3]
+            Cli.parse_args %w[--explain src/file.cr:a:3]
           end
         end
 
         it "raises an error if column number is not valid" do
           expect_raises(Exception, "location should have PATH:line:column") do
-            Cli.parse_args %w[--explain spec/fixtures/source.cr:3:&]
+            Cli.parse_args %w[--explain src/file.cr:3:&]
           end
         end
 
         it "raises an error if line/column are missing" do
           expect_raises(Exception, "location should have PATH:line:column") do
-            Cli.parse_args %w[--explain spec/fixtures/source.cr]
+            Cli.parse_args %w[--explain src/file.cr]
           end
         end
       end
diff --git a/spec/ameba/config_spec.cr b/spec/ameba/config_spec.cr
index bfc9994c..4d6f95f0 100644
--- a/spec/ameba/config_spec.cr
+++ b/spec/ameba/config_spec.cr
@@ -9,21 +9,10 @@ module Ameba
     end
 
     describe ".new" do
-      context "when config is empty" do
-        it "loads default globs" do
-          yml = YAML.parse "{}"
-          config = Config.new(yml)
-          config.globs.should eq ["**/*.cr"]
-        end
-
-        it "sets !lib as a default glob when there are .cr files in lib" do
-          File.touch "lib/shard.cr"
-          yml = YAML.parse "{}"
-          config = Config.new(yml)
-          config.globs.should eq ["**/*.cr", "!lib"]
-        ensure
-          File.delete "lib/shard.cr"
-        end
+      it "loads default globs when config is empty" do
+        yml = YAML.parse "{}"
+        config = Config.new(yml)
+        config.globs.should eq Config::DEFAULT_GLOBS
       end
 
       it "initializes globs as string" do
@@ -113,7 +102,7 @@ module Ameba
       config = Config.load config_sample
 
       it "holds source globs" do
-        config.globs.should eq ["**/*.cr"]
+        config.globs.should eq Config::DEFAULT_GLOBS
       end
 
       it "allows to set globs" do
diff --git a/spec/ameba/glob_utils_spec.cr b/spec/ameba/glob_utils_spec.cr
index fc47bacd..41309195 100644
--- a/spec/ameba/glob_utils_spec.cr
+++ b/spec/ameba/glob_utils_spec.cr
@@ -45,30 +45,6 @@ module Ameba
         subject.expand(["**/#{current_file_basename}", "**/#{current_file_basename}"])
           .should eq [current_file_path]
       end
-
-      it "raises an ArgumentError when the glob doesn't match any files" do
-        expect_raises(ArgumentError, "No files found matching foo/*") do
-          subject.expand(["foo/*"])
-        end
-      end
-
-      it "raises an ArgumentError when given a missing file" do
-        expect_raises(ArgumentError, "No files found matching foo.cr") do
-          subject.expand(["foo.cr"])
-        end
-      end
-
-      it "raises an ArgumentError when given a missing directory" do
-        expect_raises(ArgumentError, "No files found matching foo/") do
-          subject.expand(["foo/"])
-        end
-      end
-
-      it "raises an ArgumentError when given multiple arguments, one of which is missing" do
-        expect_raises(ArgumentError, "No files found matching foo.cr") do
-          subject.expand(["**/#{current_file_basename}", "foo.cr"])
-        end
-      end
     end
   end
 end
diff --git a/spec/fixtures/config.yml b/spec/fixtures/config.yml
index 4cc49722..c5394b90 100644
--- a/spec/fixtures/config.yml
+++ b/spec/fixtures/config.yml
@@ -1,4 +1,2 @@
-Ameba/PerfRule:
-  Enabled: false
-Ameba/ErrorRule:
-  Enabled: false
+Lint/ComparisonToBoolean:
+  Enabled: true
diff --git a/spec/fixtures/source.cr b/spec/fixtures/source.cr
deleted file mode 100644
index e69de29b..00000000
diff --git a/src/ameba/config.cr b/src/ameba/config.cr
index 428b89ec..49802a70 100644
--- a/src/ameba/config.cr
+++ b/src/ameba/config.cr
@@ -55,7 +55,10 @@ class Ameba::Config
     Path[XDG_CONFIG_HOME] / "ameba/config.yml",
   }
 
-  SOURCES_GLOB = "**/*.cr"
+  DEFAULT_GLOBS = %w(
+    **/*.cr
+    !lib
+  )
 
   getter rules : Array(Rule::Base)
   property severity = Severity::Convention
@@ -92,7 +95,7 @@ class Ameba::Config
     @rules = Rule.rules.map &.new(config).as(Rule::Base)
     @rule_groups = @rules.group_by &.group
     @excluded = load_array_section(config, "Excluded")
-    @globs = load_array_section(config, "Globs", default_globs)
+    @globs = load_array_section(config, "Globs", DEFAULT_GLOBS)
 
     return unless formatter_name = load_formatter_name(config)
     self.formatter = formatter_name
@@ -236,12 +239,6 @@ class Ameba::Config
     end
   end
 
-  private def default_globs
-    [SOURCES_GLOB].tap do |globs|
-      globs.push("!lib") unless Dir["lib/**/*.cr"].empty?
-    end
-  end
-
   # :nodoc:
   module RuleConfig
     # Define rule properties
diff --git a/src/ameba/glob_utils.cr b/src/ameba/glob_utils.cr
index df4e80bd..71cd0cb5 100644
--- a/src/ameba/glob_utils.cr
+++ b/src/ameba/glob_utils.cr
@@ -22,7 +22,6 @@ module Ameba
     def expand(globs)
       globs.flat_map do |glob|
         glob += "/**/*.cr" if File.directory?(glob)
-        raise ArgumentError.new("No files found matching #{glob}") if Dir[glob].empty?
         Dir[glob]
       end.uniq!
     end