diff --git a/.github/run-tests.sh b/.github/run-tests.sh
deleted file mode 100755
index d4e60dc..0000000
--- a/.github/run-tests.sh
+++ /dev/null
@@ -1,28 +0,0 @@
-#!/usr/bin/env bash
-
-# sanity check
-if (( CHAPTER < 1 | CHAPTER > 20)); then
-    echo "Bogus chapter number"
-    exit 1
-fi
-
-# define the stages we're going to test
-declare -a STAGES
-if ((CHAPTER == 1)); then
-    # no --tacky or --validate stage yet
-    STAGES=(lex parse codegen run)
-elif ((CHAPTER < 5)); then
-    # --tacky but not --validate
-    STAGES=(lex parse tacky codegen run)
-elif ((CHAPTER < 19)); then
-    # all the stages!
-    STAGES=(lex parse tacky validate codegen run)
-else
-    # don't run intermediate stages for optimization tests
-    STAGES=(run)
-fi
-readonly STAGES
-
-for stage in "${STAGES[@]}"; do
-    ./test_compiler "${CC}" --chapter "${CHAPTER}" --stage "${stage}"
-done
diff --git a/.github/run_tests.py b/.github/run_tests.py
new file mode 100755
index 0000000..0bc9309
--- /dev/null
+++ b/.github/run_tests.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+import platform
+import subprocess
+import sys
+
+# get/sanity check chapter number
+cc = sys.argv[1]
+chapter = int(sys.argv[2])
+if chapter < 1 or chapter > 20:
+    exit("Bad chapter number")
+
+# do we need rosetta?
+prefix = ""
+if platform.machine().lower() == "arm64":
+    prefix = "arch -x86_64 "
+
+# define the stages we're going to test
+stages = ["lex", "parse", "tacky", "validate", "codegen", "run"]
+if chapter == 1:
+    # tacky and validate stages not added yet
+    stages.remove("tacky")
+    stages.remove("validate")
+elif chapter < 5:
+    # TACKY stage added, validate not
+    stages.remove("validate")
+elif chapter > 18:
+    # don't test intermediate stages for chapters 19/20
+    stages = ["run"]
+
+
+for stage in stages:
+    print(f"Testing '{stage}' stage")
+    try:
+        subprocess.run(
+            f"{prefix}./test_compiler {cc} --chapter {chapter} --stage {stage}",
+            shell=True,
+            check=True,
+        )
+    except subprocess.CalledProcessError as cpe:
+        print(cpe.stderr)
+        print(cpe.stdout)
+        exit("command failed")
diff --git a/.github/workflows/build_and_test.yaml b/.github/workflows/build_and_test.yaml
index 0b319e6..f185464 100644
--- a/.github/workflows/build_and_test.yaml
+++ b/.github/workflows/build_and_test.yaml
@@ -35,8 +35,9 @@ jobs:
         with:
           repository: nlsandler/nqcc2
           sparse-checkout: |
-            .github/run-tests.sh
+            .github/run_tests.py
           sparse-checkout-cone-mode: false
+          path: script
 
       - name: Download the compiler
         uses: actions/download-artifact@v4
@@ -47,14 +48,7 @@ jobs:
       # make NQCC executable
       - run: chmod u+x nqcc/main.exe
 
-      # Invoke the run-tests script to test each intermediate stage
-
-      # use Rosetta on macOS since that's what most readers are doing
-      - name: Run the tests (Apple Silicon)
-        if: runner.arch == 'ARM64'
-        run: arch -x86_64 ./.github/run-tests.sh
-
-      - name: Run the tests (x86-64)
-        if: runner.arch != 'ARM64'
-        run: ./.github/run-tests.sh
+      # Invoke the run_tests.py script to test each intermediate stage
+      - name: Run the tests
+        run: ./script/.github/run_tests.py nqcc/main.exe "{$CHAPTER}"