diff --git a/Dangerfile b/Dangerfile
index ec04c4e..18d2173 100644
--- a/Dangerfile
+++ b/Dangerfile
@@ -7,3 +7,13 @@ end
 if git.commits.any? { |c| c.message =~ /^Merge branch '#{github.branch_for_base}'/ }
   fail('Please rebase to get rid of the merge commits in this PR')
 end
+
+# Restrict changing only one extension per PR
+if git.modified_files.grep(/^Sources\//).count > 1
+	fail("Please, modify only one extension per pull request.")
+end
+
+# Restrict changing only one test per PR
+if git.modified_files.grep(/^EZSwiftExtensionsTests\//).count > 1
+	fail("Please, modify only one extension per pull request.")
+end