diff --git a/lib/retest/runners.rb b/lib/retest/runners.rb
index 14cefc71..d3538cc8 100644
--- a/lib/retest/runners.rb
+++ b/lib/retest/runners.rb
@@ -5,6 +5,8 @@
 
 module Retest
   module Runners
+    class NotSupportedError < StandardError; end
+
     module_function
 
     def runner_for(command)
diff --git a/lib/retest/runners/runner.rb b/lib/retest/runners/runner.rb
index 6dfb4b55..8e1353f0 100644
--- a/lib/retest/runners/runner.rb
+++ b/lib/retest/runners/runner.rb
@@ -18,8 +18,7 @@ def run(changed_file = nil, repository: nil)
       end
 
       def run_all_tests(tests_string)
-        log("Test File Selected: #{tests_string}")
-        system_run command.gsub('<test>', tests_string)
+        raise NotSupportedError, 'cannot run multiple test files against this command'
       end
 
       def sync(added:, removed:)
diff --git a/lib/retest/runners/test_runner.rb b/lib/retest/runners/test_runner.rb
index 03283c71..29ee0773 100644
--- a/lib/retest/runners/test_runner.rb
+++ b/lib/retest/runners/test_runner.rb
@@ -14,6 +14,11 @@ def run(changed_file, repository:)
         system_run command.gsub('<test>', cached_test_file)
       end
 
+      def run_all_tests(tests_string)
+        log("Test File Selected: #{tests_string}")
+        system_run command.gsub('<test>', tests_string)
+      end
+
       def sync(added:, removed:)
         purge_test_file(removed)
       end
diff --git a/test/retest/runners/change_runner_test.rb b/test/retest/runners/change_runner_test.rb
index b6105ae2..1db4e82c 100644
--- a/test/retest/runners/change_runner_test.rb
+++ b/test/retest/runners/change_runner_test.rb
@@ -42,6 +42,10 @@ def test_run_with_a_file_found
 
         assert_match "touch file_path.rb", out
       end
+
+      def test_run_all_tests
+        assert_raises(NotSupportedError) { @subject.run_all_tests('file_path.rb file_path_two.rb') }
+      end
     end
   end
 end
\ No newline at end of file
diff --git a/test/retest/runners/runner_test.rb b/test/retest/runners/runner_test.rb
index 64b36378..ead003ff 100644
--- a/test/retest/runners/runner_test.rb
+++ b/test/retest/runners/runner_test.rb
@@ -35,17 +35,7 @@ def test_run
       end
 
       def test_run_all_tests
-        runner = Runner.new("echo '<test>'", stdout: StringIO.new)
-
-        out, _ = capture_subprocess_io { runner.run_all_tests('file_path.rb file_path_two.rb') }
-
-        assert_equal(<<~EXPECATIONS, runner.stdout.string)
-        Test File Selected: file_path.rb file_path_two.rb
-        EXPECATIONS
-
-        assert_equal(<<~EXPECATIONS, out)
-        file_path.rb file_path_two.rb
-        EXPECATIONS
+        assert_raises(NotSupportedError) { @subject.run_all_tests('file_path.rb file_path_two.rb') }
       end
     end
   end
diff --git a/test/retest/runners/test_runner_test.rb b/test/retest/runners/test_runner_test.rb
index e73341c6..c2bb8849 100644
--- a/test/retest/runners/test_runner_test.rb
+++ b/test/retest/runners/test_runner_test.rb
@@ -74,6 +74,18 @@ def test_sync_files
         @subject.sync(added: 'a.rb', removed:'file_path_test.rb')
         assert_nil @subject.cached_test_file
       end
+
+      def test_run_all_tests
+        out, _ = capture_subprocess_io { @subject.run_all_tests('file_path.rb file_path_two.rb') }
+
+        assert_equal(<<~EXPECATIONS, @subject.stdout.string)
+          Test File Selected: file_path.rb file_path_two.rb
+        EXPECATIONS
+
+        assert_equal(<<~EXPECATIONS, out)
+          touch file_path.rb file_path_two.rb
+        EXPECATIONS
+      end
     end
   end
 end
\ No newline at end of file
diff --git a/test/retest/runners/variable_runner_test.rb b/test/retest/runners/variable_runner_test.rb
index 01c2fcde..bf766fda 100644
--- a/test/retest/runners/variable_runner_test.rb
+++ b/test/retest/runners/variable_runner_test.rb
@@ -85,6 +85,10 @@ def test_sync_files
         @subject.sync(added: 'a.rb', removed:'file_path_test.rb')
         assert_nil @subject.cached_test_file
       end
+
+      def test_run_all_tests
+        assert_raises(NotSupportedError) { @subject.run_all_tests('file_path.rb file_path_two.rb') }
+      end
     end
   end
 end
\ No newline at end of file