diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..bd1298c
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,13 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+### Added
+
+- Initial Ruzzy implementation
+- Support for fuzzing Ruby C extensions
diff --git a/ext/cruzzy/extconf.rb b/ext/cruzzy/extconf.rb
index 0db675e..54d4b10 100644
--- a/ext/cruzzy/extconf.rb
+++ b/ext/cruzzy/extconf.rb
@@ -4,22 +4,36 @@
 require 'open3'
 require 'tempfile'
 
-CC = 'clang'
-CXX = 'clang++'
+# These ENV variables really shouldn't be used because we don't support
+# compilers other than clang, like gcc, etc. Instead prefer to properly include
+# clang in your PATH. But they're here if you really need them. Also note that
+# *technically* Ruby does not support C extensions compiled with a different
+# compiler than Ruby itself was compiled with. So we're on somewhat shaky
+# ground here. For more information see:
+# https://github.com/rubygems/rubygems/issues/1508
+CC = ENV.fetch('CC', 'clang')
+CXX = ENV.fetch('CXX', 'clang++')
 FUZZER_NO_MAIN_LIB_ENV = 'FUZZER_NO_MAIN_LIB'
 
 find_executable(CC)
+find_executable(CXX)
 
 def get_clang_file_name(file_name)
+  puts("Searching for #{file_name} using #{CC}")
   stdout, status = Open3.capture2(CC, '--print-file-name', file_name)
+  puts("Search command succeeded: #{status.success?}")
+  puts("Search file exists: #{File.exist?(stdout.strip)}") if status.success?
   status.success? && File.exist?(stdout.strip) ? stdout.strip : false
 end
 
 def merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
+  merged_output = 'asan_with_fuzzer.so'
+
   # https://github.com/google/atheris/blob/master/native_extension_fuzzing.md#why-this-is-necessary
   Tempfile.create do |file|
     file.write(File.open(asan_lib).read)
 
+    puts("Creating ASAN archive at #{file.path}")
     _, status = Open3.capture2(
       'ar',
       'd',
@@ -32,6 +46,7 @@ def merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
       exit(1)
     end
 
+    puts("Merging ASAN at #{file.path} and libFuzzer at #{fuzzer_no_main_lib} to #{merged_output}")
     _, status = Open3.capture2(
       CXX,
       '-Wl,--whole-archive',
@@ -42,7 +57,7 @@ def merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
       '-ldl',
       '-shared',
       '-o',
-      'asan_with_fuzzer.so'
+      merged_output
     )
     unless status.success?
       puts("The 'clang' shared object merging command failed.")
@@ -68,11 +83,6 @@ def merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
   end
 end
 
-# The LOCAL_LIBS variable allows linking arbitrary libraries into Ruby C
-# extensions. It is supported by the Ruby mkmf library and C extension Makefile.
-# For more information, see https://github.com/ruby/ruby/blob/master/lib/mkmf.rb.
-$LOCAL_LIBS = fuzzer_no_main_lib
-
 asan_libs = [
   'libclang_rt.asan.a',
   'libclang_rt.asan-aarch64.a',
@@ -87,4 +97,9 @@ def merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
 
 merge_asan_libfuzzer_lib(asan_lib, fuzzer_no_main_lib)
 
+# The LOCAL_LIBS variable allows linking arbitrary libraries into Ruby C
+# extensions. It is supported by the Ruby mkmf library and C extension Makefile.
+# For more information, see https://github.com/ruby/ruby/blob/master/lib/mkmf.rb.
+$LOCAL_LIBS = fuzzer_no_main_lib
+
 create_makefile('cruzzy/cruzzy')
diff --git a/test/test_ruzzy.rb b/test/test_ruzzy.rb
index 5c96bdc..12ef9a2 100644
--- a/test/test_ruzzy.rb
+++ b/test/test_ruzzy.rb
@@ -47,6 +47,22 @@ def test_fuzz_without_proc
     end
   end
 
+  def test_fuzz_without_args
+    dummy_test_one_input = ->(data) { Ruzzy.dummy_test_one_input(data) }
+
+    assert_raise(RuntimeError) do
+      Ruzzy.fuzz(dummy_test_one_input, [])
+    end
+  end
+
+  def test_fuzz_with_too_many_args
+    dummy_test_one_input = ->(data) { Ruzzy.dummy_test_one_input(data) }
+
+    assert_raise(RuntimeError) do
+      Ruzzy.fuzz(dummy_test_one_input, Array.new(128, 'test'))
+    end
+  end
+
   def test_ext_path
     assert(Ruzzy.ext_path)
   end