diff --git a/lib/core/src/test_runner.ri b/lib/core/src/test_runner.ri
index 65a4eb342..205326e74 100644
--- a/lib/core/src/test_runner.ri
+++ b/lib/core/src/test_runner.ri
@@ -93,7 +93,9 @@ public struct TestRunner {
             }
         }
         self.print_summary_tests();
-        process_exit(@as(int32, self.fail_tests));
+        if self.fail_tests > 0 {
+            process_exit(1);
+        }
     }
 
     func print_summary_tests(&self) {
diff --git a/rivetc/src/__init__.py b/rivetc/src/__init__.py
index 30e0f2445..41969ffe4 100644
--- a/rivetc/src/__init__.py
+++ b/rivetc/src/__init__.py
@@ -57,8 +57,6 @@ def __init__(self, args):
         self.checker = checker.Checker(self)
         self.codegen = codegen.Codegen(self)
 
-        self.exit_code = 0
-
     def import_modules(self):
         for sf in self.parsed_files:
             for decl in sf.decls:
@@ -147,8 +145,6 @@ def run(self):
                 self.codegen.gen_source_files(self.source_files)
                 if report.ERRORS > 0:
                     self.abort()
-            if self.exit_code != 0:
-                exit(self.exit_code)
 
     def load_root_module(self):
         if path.isdir(self.prefs.input):
diff --git a/rivetc/src/codegen/__init__.py b/rivetc/src/codegen/__init__.py
index 96363d089..13baa09d3 100644
--- a/rivetc/src/codegen/__init__.py
+++ b/rivetc/src/codegen/__init__.py
@@ -276,8 +276,11 @@ def gen_source_files(self, source_files):
                 self.comp.vlog("generating C output from RIR...")
                 CGen(self.comp).gen(self.out_rir)
             if self.comp.prefs.build_mode == prefs.BuildMode.Test:
-                self.comp.exit_code = os.system(self.comp.prefs.mod_output)
+                exit_code = os.system(self.comp.prefs.mod_output)
                 os.remove(self.comp.prefs.mod_output)
+                # assert exit_code == 0
+                if exit_code != 0:
+                    exit(1)
 
     def gen_mod_attributes(self, mod_name, attributes):
         mod_folder = os.path.join(prefs.RIVET_DIR, "obj", mod_name)
diff --git a/rivetc/src/prefs.py b/rivetc/src/prefs.py
index 7fc8f8dae..e117e3961 100644
--- a/rivetc/src/prefs.py
+++ b/rivetc/src/prefs.py
@@ -298,7 +298,7 @@ def __init__(self, args: [str]):
         self.build_rivet_dir()
 
         if self.build_mode == BuildMode.Test:
-            self.mod_output = f"_tests_runner_"
+            self.mod_output = f"_tests_runner__{self.mod_name}_"
         elif len(self.mod_output) == 0:
             self.mod_output = self.mod_name
         if self.target_os == OS.Windows and not self.mod_output.endswith(