diff --git a/auto/unity_test_summary.rb b/auto/unity_test_summary.rb
index 05930381..a91d9cde 100755
--- a/auto/unity_test_summary.rb
+++ b/auto/unity_test_summary.rb
@@ -124,7 +124,7 @@ def parse_test_summary(summary)
   begin
     # look in the specified or current directory for result files
     args[0] ||= './'
-    targets = "#{ARGV[0].tr('\\', '/')}**/*.test*"
+    targets = "#{args[0].tr('\\', '/')}**/*.test*"
     results = Dir[targets]
 
     raise "No *.testpass, *.testfail, or *.testresults files found in '#{targets}'" if results.empty?
@@ -133,7 +133,7 @@ def parse_test_summary(summary)
 
     # set the root path
     args[1] ||= "#{Dir.pwd}/"
-    uts.root = ARGV[1]
+    uts.root = args[1]
 
     # run the summarizer
     puts uts.run
diff --git a/docs/UnityChangeLog.md b/docs/UnityChangeLog.md
index d1eab9a3..6e73e27c 100644
--- a/docs/UnityChangeLog.md
+++ b/docs/UnityChangeLog.md
@@ -18,6 +18,7 @@ Prior to 2008, the project was an internal project and not released to the publi
 Significant Bugfixes:
 
   - Default `UNITY_INCLUDE_EXEC_TIME` macros compile as ISO C99, are statement-safe, and accept `-Wsign-conversion` (#838)
+  - `unity_test_summary.rb` honors its own default result directory and root path again. @youdie006
 
 ### Unity 2.7.0 (July 2026)
 
diff --git a/test/tests/test_unity_test_summary.rb b/test/tests/test_unity_test_summary.rb
new file mode 100644
index 00000000..72cc0636
--- /dev/null
+++ b/test/tests/test_unity_test_summary.rb
@@ -0,0 +1,58 @@
+# =========================================================================
+#   Unity - A Test Framework for C
+#   ThrowTheSwitch.org
+#   Copyright (c) 2007-26 Mike Karlesky, Mark VanderVoord, & Greg Williams
+#   SPDX-License-Identifier: MIT
+# =========================================================================
+
+require 'fileutils'
+require_relative '../../auto/colour_reporter'
+
+# the 'test:scripts' rake task tallies these, so only initialize them if we are loaded first
+$generate_test_runner_tests ||= 0
+$generate_test_runner_failures ||= 0
+$unity_test_summary_failures = 0
+
+SUMMARY_SCRIPT  = File.expand_path('../../auto/unity_test_summary.rb', __dir__)
+SUMMARY_SANDBOX = File.expand_path('../sandbox/test_summary', __dir__)
+SUMMARY_RESULTS = <<~RESULTS
+  test/test_a.c:12:test_thing:PASS
+  test/test_b.c:34:test_broken:FAIL: Expected 1 Was 2
+  test/test_c.c:56:test_skipped:IGNORE: not ready
+
+  -----------------------
+  3 Tests 1 Failures 1 Ignored
+RESULTS
+
+def summary_test(name, passed)
+  if passed
+    report "#{name}:PASS"
+  else
+    report "#{name}:FAIL"
+    $generate_test_runner_failures += 1
+    $unity_test_summary_failures += 1
+  end
+  $generate_test_runner_tests += 1
+end
+
+FileUtils.rm_rf(SUMMARY_SANDBOX)
+FileUtils.mkdir_p(SUMMARY_SANDBOX)
+File.write(File.join(SUMMARY_SANDBOX, 'test_sample.testfail'), SUMMARY_RESULTS)
+
+begin
+  Dir.chdir(SUMMARY_SANDBOX) do
+    # with no arguments at all, the result files are looked for in the current directory
+    output = `ruby "#{SUMMARY_SCRIPT}" 2>&1`
+    summary_test('UnityTestSummary_DefaultsResultDirectoryToCurrentDirectory',
+                 $?.success? && output.include?('3 TOTAL TESTS 1 TOTAL FAILURES 1 IGNORED'))
+
+    # with only a result directory given, the root path defaults to the current directory
+    expected = "#{Dir.pwd}/test/test_b.c:34".tr('/', '\\')
+    output = `ruby "#{SUMMARY_SCRIPT}" ./ 2>&1`
+    summary_test('UnityTestSummary_DefaultsRootPathToCurrentDirectory', output.include?(expected))
+  end
+ensure
+  FileUtils.rm_rf(SUMMARY_SANDBOX)
+end
+
+raise "There were #{$unity_test_summary_failures} failures while testing unity_test_summary.rb" if $unity_test_summary_failures > 0