diff --git a/lua_tests/expectnmcu/core.tcl b/lua_tests/expectnmcu/core.tcl
new file mode 100644
index 0000000000..9827ab0bfd
--- /dev/null
+++ b/lua_tests/expectnmcu/core.tcl
@@ -0,0 +1,55 @@
+namespace eval expectnmcu::core {
+}
+
+# Establish a serial connection to the device via socat
+proc ::expectnmcu::core::connect { dev baud } {
+  spawn "socat" "STDIO" "${dev},b${baud},rawer,crnl"
+  close -onexec 1 -i ${spawn_id}
+  return ${spawn_id}
+}
+
+# Use DTR/RTS signaling to reboot the device
+## I'm not sure why we have to keep resetting the mode, but so it goes.
+proc ::expectnmcu::core::reboot { dev baud } {
+  set victimfd [open "${dev}"]
+  fconfigure ${victimfd} -mode ${baud},n,8,1 -ttycontrol {DTR 0 RTS 1}
+  sleep 0.1
+  fconfigure ${victimfd} -mode ${baud},n,8,1 -ttycontrol {DTR 0 RTS 0}
+  close ${victimfd}
+}
+
+proc ::expectnmcu::core::waitboot { victim } {
+  expect {
+    -i ${victim} "Formatting file system" {
+      set timeout 60
+      exp_continue
+    }
+    -i ${victim} "powered by Lua" { }
+    timeout { return -code error "Timeout" }
+  }
+  # Catch nwf's system bootup, in case we're testing an existing system,
+  # rather than a blank firmware.
+  expect {
+    -i ${victim} "Reset delay!" { send "got:stop()\n" ; expect "> " }
+    -i ${victim} "> " { }
+    timeout { return -code error "Timeout" }
+  }
+}
+
+proc ::expectnmcu::core::send_exp_prompt { sid cmd } {
+  send -i ${sid} -- "${cmd}\n"
+  expect {
+   -i ${sid} -ex "\n> " { }
+   timeout { return -code error "Timeout" }
+  }
+}
+
+proc ::expectnmcu::core::send_exp_prompt_c { sid cmd } {
+  send -i ${sid} -- "${cmd}\n"
+  expect {
+   -i ${sid} -ex "\n>> " { }
+   timeout { return -code error "Timeout" }
+  }
+}
+
+package provide expectnmcu::core 1.0
diff --git a/lua_tests/expectnmcu/pkgIndex.tcl b/lua_tests/expectnmcu/pkgIndex.tcl
new file mode 100644
index 0000000000..5b74575461
--- /dev/null
+++ b/lua_tests/expectnmcu/pkgIndex.tcl
@@ -0,0 +1,11 @@
+# Tcl package index file, version 1.1
+# This file is generated by the "pkg_mkIndex" command
+# and sourced either when an application starts up or
+# by a "package unknown" script.  It invokes the
+# "package ifneeded" command to set up package-related
+# information so that packages will be loaded automatically
+# in response to "package require" commands.  When this
+# script is sourced, the variable $dir must contain the
+# full path name of this file's directory.
+
+package ifneeded expectnmcu::core 1.0 [list source [file join $dir core.tcl]]
diff --git a/lua_tests/tls-test.expect b/lua_tests/tls-test.expect
index 3aa2cc585d..bc92f228a0 100644
--- a/lua_tests/tls-test.expect
+++ b/lua_tests/tls-test.expect
@@ -8,7 +8,7 @@
 # overridden with the -ip command line option.
 #
 # A typical invocation looks like:
-#   ./tls-test.expect -serial /dev/ttyUSB3 -wifi "$(cat wificmd)"
+#   TCLLIBPATH=./expectnmcu ./tls-test.expect -serial /dev/ttyUSB3 -wifi "$(cat wificmd)"
 #
 # where the file `wificmd` contains something like
 #  wifi.setmode(wifi.STATION); wifi.sta.config({...}); wifi.sta.connect()
@@ -18,10 +18,11 @@
 # For debugging the test itself, it may be useful to invoke expect with -d,
 # which will give a great deal of diagnostic information about the expect state
 # machine's internals:
-#   expect -d ./tls-test.expect ...
+#   TCLLIBPATH=./expectnmcu expect -d ./tls-test.expect ...
 
 
 package require struct::stack
+package require expectnmcu::core
 
 ::struct::stack ulogstack
 proc pushulog { new } {
@@ -30,20 +31,6 @@ proc pushulog { new } {
 }
 proc populog { } { log_user [ulogstack pop] }
 
-proc send_exp_prompt { sid cmd } {
-  send -i ${sid} -- "${cmd}\n"
-  expect {
-   -i ${sid} -ex "\n> " { }
-  }
-}
-
-proc send_exp_prompt_c { sid cmd } {
-  send -i ${sid} -- "${cmd}\n"
-  expect {
-   -i ${sid} -ex "\n>> " { }
-  }
-}
-
 proc genectls { curve pfx } {
   exec "openssl" "ecparam" "-genkey" "-name" ${curve} "-out" "${pfx}.key"
   exec "openssl" "req" "-new" "-sha256" "-subj" "/CN=${curve}" "-key" "${pfx}.key" "-out" "${pfx}.csr"
@@ -51,14 +38,14 @@ proc genectls { curve pfx } {
 }
 
 proc preptls { victim } {
-  send_exp_prompt_c ${victim} "function tlsbasic(id,port,host)"
-  send_exp_prompt_c ${victim} "  local c = tls.createConnection()"
-  send_exp_prompt_c ${victim} "  c:on(\"receive\", function(sck, d) print(\"RECV\",id,d) end)"
-  send_exp_prompt_c ${victim} "  c:on(\"connection\", function(sck) print(\"CONN\",id); sck:send(\"GET / HTTP/1.0\\r\\n\\r\\n\") end)"
-  send_exp_prompt_c ${victim} "  c:on(\"disconnection\", function(sck) print(\"DISC\",id) end)"
-  send_exp_prompt_c ${victim} "  c:connect(port,host)"
-  send_exp_prompt_c ${victim} "  return c"
-  send_exp_prompt   ${victim} "end"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "function tlsbasic(id,port,host)"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  local c = tls.createConnection()"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  c:on(\"receive\", function(sck, d) print(\"RECV\",id,d) end)"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  c:on(\"connection\", function(sck) print(\"CONN\",id); sck:send(\"GET / HTTP/1.0\\r\\n\\r\\n\") end)"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  c:on(\"disconnection\", function(sck) print(\"DISC\",id) end)"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  c:connect(port,host)"
+  ::expectnmcu::core::send_exp_prompt_c ${victim} "  return c"
+  ::expectnmcu::core::send_exp_prompt   ${victim} "end"
 }
 
 # Basic connectivity test, including disconnection of localsid.
@@ -81,7 +68,7 @@ proc basicconntest { id localsid victimsid victimconn } {
   populog
   expect {
     -i ${victimsid} "RECV\t${id}\tabracadabra" {
-      send_exp_prompt ${victimsid} "${victimconn}:send(\"test 1 2 3 4\")"
+      ::expectnmcu::core::send_exp_prompt ${victimsid} "${victimconn}:send(\"test 1 2 3 4\")"
     }
   }
   pushulog 0
@@ -120,36 +107,11 @@ if {[catch {array set cmdopts [cmdline::getoptions ::argv $cmd_parameters $cmd_u
 
 send_user "===> Note: Serial port is ${cmdopts(serial)}; debug is ${cmdopts(debug)} <===\n"
 
-spawn "socat" "STDIO" "${cmdopts(serial)},rawer,crnl"
-set victim ${spawn_id}
-close -onexec 1 -i ${victim}
-
-# Use DTR/RTS signaling to reboot the device
-## I'm not sure why we have to keep resetting the mode, but so it goes.
-set victimfd [open "${cmdopts(serial)}"]
-fconfigure ${victimfd} -mode 115200,n,8,1 -ttycontrol {DTR 0 RTS 1}
-sleep 0.1
-fconfigure ${victimfd} -mode 115200,n,8,1 -ttycontrol {DTR 0 RTS 0}
-close ${victimfd}
+set victim [::expectnmcu::core::connect ${cmdopts(serial)} 115200]
+::expectnmcu::core::reboot ${cmdopts(serial)} 115200
 
 # Wait for the system to boot
-expect {
-  -i ${victim} "Formatting file system" {
-    set timeout 60
-    exp_continue
-  }
-  -i ${victim} "powered by Lua" { }
-  timeout {
-    send_user "\n===> Did not see boot sequence; bailing out <===\n"
-    exit 0
-  }
-}
-# Catch nwf's system bootup, in case we're testing an existing system,
-# rather than a blank firmware.
-expect {
-  -i ${victim} "Reset delay!" { send "got:stop()\n" ; expect "> " }
-  -i ${victim} "> " { }
-}
+::expectnmcu::core::waitboot ${victim}
 send_user "\n===> Machine has booted <===\n"
 
 # Program a routine for TLS connections
@@ -158,7 +120,7 @@ preptls ${victim}
 # Connect the board to the network
 
 if {[expr 0 < [string length ${cmdopts(wifi)}]]} {
-  send_exp_prompt ${victim} ${cmdopts(wifi)}
+  ::expectnmcu::core::send_exp_prompt ${victim} ${cmdopts(wifi)}
 }
 
 for {set i 0} {${i} < 10} {incr i} {
@@ -193,34 +155,34 @@ if {[expr 0 < [string length ${cmdopts(ip)}]]} {
   close
 }
 
-send_exp_prompt ${victim} "tls.setDebug(2)"
-send_exp_prompt ${victim} "tls.cert.verify(false)"
+::expectnmcu::core::send_exp_prompt ${victim} "tls.setDebug(2)"
+::expectnmcu::core::send_exp_prompt ${victim} "tls.cert.verify(false)"
 
 send_user "\n===> TEST SSL 256v1, no verify <===\n"
 
 spawn -noecho "socat" "STDIO,cfmakeraw" "OPENSSL-LISTEN:12345,verify=0,certificate=${fntls256v1}.crt,key=${fntls256v1}.key,reuseaddr"
-send_exp_prompt ${victim} "c = tlsbasic(0,12345,\"${myip}\")"
+::expectnmcu::core::send_exp_prompt ${victim} "c = tlsbasic(0,12345,\"${myip}\")"
 basicconntest 0 ${spawn_id} ${victim} "c"
 
 send_user "\n===> TEST SSL 384r1, no verify <===\n"
 
 spawn -noecho "socat" "STDIO,cfmakeraw" "OPENSSL-LISTEN:12345,verify=0,certificate=${fntls384r1}.crt,key=${fntls384r1}.key,reuseaddr"
-send_exp_prompt ${victim} "c = tlsbasic(1,12345,\"${myip}\")"
+::expectnmcu::core::send_exp_prompt ${victim} "c = tlsbasic(1,12345,\"${myip}\")"
 basicconntest 1 ${spawn_id} ${victim} "c"
 
 send_user "\n===> TEST SSL 384r1, verify <===\n"
 
 set cert [open "${fntls384r1}.crt"]
-send_exp_prompt_c ${victim} "tls.cert.verify(\[\["
+::expectnmcu::core::send_exp_prompt_c ${victim} "tls.cert.verify(\[\["
 while { [gets $cert line] >= 0 } {
-  send_exp_prompt_c ${victim} $line
+  ::expectnmcu::core::send_exp_prompt_c ${victim} $line
 }
-send_exp_prompt ${victim} "]])"
+::expectnmcu::core::send_exp_prompt ${victim} "]])"
 close ${cert}
-send_exp_prompt ${victim} "tls.cert.verify(true)"
+::expectnmcu::core::send_exp_prompt ${victim} "tls.cert.verify(true)"
 
 spawn -noecho "socat" "STDIO,cfmakeraw" "OPENSSL-LISTEN:12345,verify=0,certificate=${fntls384r1}.crt,key=${fntls384r1}.key,reuseaddr"
-send_exp_prompt ${victim} "c = tlsbasic(2,12345,\"${myip}\")"
+::expectnmcu::core::send_exp_prompt ${victim} "c = tlsbasic(2,12345,\"${myip}\")"
 basicconntest 2 ${spawn_id} ${victim} "c"
 
 send_user "\n===> TESTS OK <===\n"