diff --git a/.travis.yml b/.travis.yml
index 27316ec..41cc3e8 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -6,4 +6,4 @@ services: docker
 before_install: docker pull verilator/verilator:latest
 
 script:
-        docker run --rm -t -v `pwd`:/build -w /build --entrypoint /bin/bash verilator/verilator:latest -c "apt update; apt install -y default-jre-headless gnupg; apt update; echo 'deb https://dl.bintray.com/sbt/debian /' | tee -a /etc/apt/sources.list.d/sbt.list; apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823; apt update; apt install -y sbt; make; make check"
+        docker run --rm -t -v `pwd`:/build -w /build --entrypoint /bin/bash verilator/verilator:latest -c "apt update; apt install -y default-jre-headless gnupg python3-pexpect; apt update; echo 'deb https://dl.bintray.com/sbt/debian /' | tee -a /etc/apt/sources.list.d/sbt.list; apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2EE0EA64E40A89B84B2DF73499E82A75642AC823; apt update; apt install -y sbt; make; make check; ./scripts/test_micropython_long.py"
diff --git a/scripts/test_micropython_long.py b/scripts/test_micropython_long.py
new file mode 100755
index 0000000..9191ee2
--- /dev/null
+++ b/scripts/test_micropython_long.py
@@ -0,0 +1,49 @@
+#!/usr/bin/python3
+
+import tempfile
+import os
+from shutil import copyfile
+import subprocess
+from pexpect import fdpexpect
+import sys
+import signal
+
+tempdir = tempfile.TemporaryDirectory()
+cwd = os.getcwd()
+os.chdir(tempdir.name)
+
+copyfile(os.path.join(cwd, 'micropython/firmware.hex'),
+        os.path.join(tempdir.name, 'insns.hex'))
+
+cmd = [ os.path.join(cwd, 'chiselwatt') ]
+
+devNull = open(os.devnull, 'w')
+p = subprocess.Popen(cmd, stdout=subprocess.PIPE,
+        stdin=subprocess.PIPE, stderr=subprocess.PIPE)
+
+exp = fdpexpect.fdspawn(p.stdout)
+exp.logfile = sys.stdout.buffer
+
+exp.expect('Type "help\(\)" for more information.')
+exp.expect('>>>')
+
+p.stdin.write(b'n2=0\r\n')
+p.stdin.write(b'n1=1\r\n')
+p.stdin.write(b'for i in range(30):\r\n')
+p.stdin.write(b'    n0 = n1 + n2\r\n')
+p.stdin.write(b'    print(n0)\r\n')
+p.stdin.write(b'    n2 = n1\r\n')
+p.stdin.write(b'    n1 = n0\r\n')
+p.stdin.write(b'\r\n')
+p.stdin.flush()
+
+exp.expect('n1 = n0', timeout=60)
+n2 = 0
+n1 = 1
+for i in range(30):
+    n0 = n1 + n2
+    exp.expect("%s" % n0, timeout=60)
+    n2 = n1
+    n1 = n0
+
+os.kill(p.pid, signal.SIGKILL)